We've changed some things in a project of ours (authentication) in order to use an XML catalog.
Since we've done that, I get the following error when building this project:

[FINDBUGS] Parsing of file /ige/hudson/work/jobs/auth/workspace/auth-api/target/findbugsXml.xml failed due to an exception:

org.dom4j.DocumentException: Sax error Nested exception: SAX2 driver class org.apache.xerces.parsers.SAXParser not found
at edu.umd.cs.findbugs.SortedBugCollection.doReadXML(SortedBugCollection.java:279)
at edu.umd.cs.findbugs.SortedBugCollection.readXML(SortedBugCollection.java:263)
at hudson.plugins.findbugs.parser.FindBugsParser.parse(FindBugsParser.java:193)
at hudson.plugins.findbugs.parser.FindBugsParser.parse(FindBugsParser.java:129)
at hudson.plugins.findbugs.parser.FindBugsParser.parse(FindBugsParser.java:89)
at hudson.plugins.analysis.core.FilesParser.parseFile(FilesParser.java:152)
at hudson.plugins.analysis.core.FilesParser.parseFiles(FilesParser.java:131)
at hudson.plugins.analysis.core.FilesParser.invoke(FilesParser.java:87)
at hudson.plugins.analysis.core.FilesParser.invoke(FilesParser.java:28)
at hudson.FilePath.act(FilePath.java:753)
at hudson.FilePath.act(FilePath.java:735)
at hudson.plugins.findbugs.FindBugsReporter.perform(FindBugsReporter.java:123)
at hudson.plugins.analysis.core.HealthAwareMavenReporter.postExecute(HealthAwareMavenReporter.java:197)
at hudson.maven.MavenModuleSetBuild$Builder.postExecute(MavenModuleSetBuild.java:757)
at hudson.maven.MavenBuilder$Adapter.postExecute(MavenBuilder.java:293)
at hudson.maven.agent.PluginManagerInterceptor$1MojoIntercepterImpl.callPost(PluginManagerInterceptor.java:170)
at hudson.maven.agent.PluginManagerInterceptor.executeMojo(PluginManagerInterceptor.java:183)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:678)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:540)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:519)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:371)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:332)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:181)
at org.apache.maven.lifecycle.LifecycleExecutorInterceptor.execute(LifecycleExecutorInterceptor.java:65)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:356)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:137)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at hudson.maven.agent.Main.launch(Main.java:165)
at hudson.maven.MavenBuilder.call(MavenBuilder.java:165)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:696)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:640)
at hudson.remoting.UserRequest.perform(UserRequest.java:114)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException: org.apache.xerces.parsers.SAXParser
at org.xml.sax.helpers.XMLReaderFactory.loadClass(XMLReaderFactory.java:189)
at org.xml.sax.helpers.XMLReaderFactory.createXMLReader(XMLReaderFactory.java:150)
at edu.umd.cs.findbugs.SortedBugCollection.doReadXML(SortedBugCollection.java:276)
... 45 more
Caused by: java.lang.ClassNotFoundException: org.apache.xerces.parsers.SAXParser
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at org.codehaus.classworlds.RealmClassLoader.loadClassDirect(RealmClassLoader.java:195)
at org.codehaus.classworlds.DefaultClassRealm.loadClass(DefaultClassRealm.java:255)
at org.codehaus.classworlds.DefaultClassRealm.loadClass(DefaultClassRealm.java:274)
at org.codehaus.classworlds.RealmClassLoader.loadClass(RealmClassLoader.java:214)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at org.xml.sax.helpers.NewInstance.newInstance(NewInstance.java:49)
at org.xml.sax.helpers.XMLReaderFactory.loadClass(XMLReaderFactory.java:187)
... 47 more
Nested exception:
java.lang.ClassNotFoundException: org.apache.xerces.parsers.SAXParser
at org.xml.sax.helpers.XMLReaderFactory.loadClass(XMLReaderFactory.java:189)
at org.xml.sax.helpers.XMLReaderFactory.createXMLReader(XMLReaderFactory.java:150)
at edu.umd.cs.findbugs.SortedBugCollection.doReadXML(SortedBugCollection.java:276)
at edu.umd.cs.findbugs.SortedBugCollection.readXML(SortedBugCollection.java:263)
at hudson.plugins.findbugs.parser.FindBugsParser.parse(FindBugsParser.java:193)
at hudson.plugins.findbugs.parser.FindBugsParser.parse(FindBugsParser.java:129)
at hudson.plugins.findbugs.parser.FindBugsParser.parse(FindBugsParser.java:89)
at hudson.plugins.analysis.core.FilesParser.parseFile(FilesParser.java:152)
at hudson.plugins.analysis.core.FilesParser.parseFiles(FilesParser.java:131)
at hudson.plugins.analysis.core.FilesParser.invoke(FilesParser.java:87)
at hudson.plugins.analysis.core.FilesParser.invoke(FilesParser.java:28)
at hudson.FilePath.act(FilePath.java:753)
at hudson.FilePath.act(FilePath.java:735)
at hudson.plugins.findbugs.FindBugsReporter.perform(FindBugsReporter.java:123)
at hudson.plugins.analysis.core.HealthAwareMavenReporter.postExecute(HealthAwareMavenReporter.java:197)
at hudson.maven.MavenModuleSetBuild$Builder.postExecute(MavenModuleSetBuild.java:757)
at hudson.maven.MavenBuilder$Adapter.postExecute(MavenBuilder.java:293)
at hudson.maven.agent.PluginManagerInterceptor$1MojoIntercepterImpl.callPost(PluginManagerInterceptor.java:170)
at hudson.maven.agent.PluginManagerInterceptor.executeMojo(PluginManagerInterceptor.java:183)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:678)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:540)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:519)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:371)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:332)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:181)
at org.apache.maven.lifecycle.LifecycleExecutorInterceptor.execute(LifecycleExecutorInterceptor.java:65)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:356)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:137)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at hudson.maven.agent.Main.launch(Main.java:165)
at hudson.maven.MavenBuilder.call(MavenBuilder.java:165)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:696)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:640)
at hudson.remoting.UserRequest.perform(UserRequest.java:114)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException: org.apache.xerces.parsers.SAXParser
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at org.codehaus.classworlds.RealmClassLoader.loadClassDirect(RealmClassLoader.java:195)
at org.codehaus.classworlds.DefaultClassRealm.loadClass(DefaultClassRealm.java:255)
at org.codehaus.classworlds.DefaultClassRealm.loadClass(DefaultClassRealm.java:274)
at org.codehaus.classworlds.RealmClassLoader.loadClass(RealmClassLoader.java:214)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at org.xml.sax.helpers.NewInstance.newInstance(NewInstance.java:49)
at org.xml.sax.helpers.XMLReaderFactory.loadClass(XMLReaderFactory.java:187)
... 47 more