Initial symptom was exception when saving scriptler script with message indicating unable to update git. Additional symptom is error 404 response to scriptler Git repo link. Reverting to Git Server plugin version 1.3 restores normal functionality.

This start-up exception may be related:
ct 17, 2014 6:14:17 PM hudson.ExtensionFinder$GuiceFinder$SezpozModule configure
WARNING: Failed to load org.jenkinsci.plugins.scriptler.git.GitScriptlerRepositorySSHAccess
java.lang.LinkageError: loader constraint violation: loader (instance of hudson/ClassicPluginStrategy$AntClassLoader2) previously initiated loading for a different type with name "org/eclipse/jgit/transport/UploadPack"
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
at jenkins.util.AntClassLoader.defineClassFromData(AntClassLoader.java:1138)
at hudson.ClassicPluginStrategy$AntClassLoader2.defineClassFromData(ClassicPluginStrategy.java:756)
at jenkins.util.AntClassLoader.getClassFromStream(AntClassLoader.java:1309)
at jenkins.util.AntClassLoader.findClassInComponents(AntClassLoader.java:1365)
at jenkins.util.AntClassLoader.findClass(AntClassLoader.java:1325)
at jenkins.util.AntClassLoader.loadClass(AntClassLoader.java:1078)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2521)
at java.lang.Class.privateGetPublicMethods(Class.java:2641)
at java.lang.Class.privateGetPublicMethods(Class.java:2657)
at java.lang.Class.getMethods(Class.java:1457)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.resolve(ExtensionFinder.java:481)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.configure(ExtensionFinder.java:508)
at com.google.inject.AbstractModule.configure(AbstractModule.java:62)
at com.google.inject.spi.Elements$RecordingBinder.install(Elements.java:230)
at com.google.inject.spi.Elements.getElements(Elements.java:103)
at com.google.inject.internal.InjectorShell$Builder.build(InjectorShell.java:136)
at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:104)
at com.google.inject.Guice.createInjector(Guice.java:96)
at com.google.inject.Guice.createInjector(Guice.java:73)
at hudson.ExtensionFinder$GuiceFinder.<init>(ExtensionFinder.java:279)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at java.lang.Class.newInstance(Class.java:374)
at net.java.sezpoz.IndexItem.instance(IndexItem.java:181)
at hudson.ExtensionFinder$Sezpoz._find(ExtensionFinder.java:639)
at hudson.ExtensionFinder$Sezpoz.find(ExtensionFinder.java:614)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:343)
at hudson.ExtensionList.load(ExtensionList.java:300)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:253)
at hudson.ExtensionList.iterator(ExtensionList.java:143)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:336)
at hudson.ExtensionList.load(ExtensionList.java:300)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:253)
at hudson.ExtensionList.getComponents(ExtensionList.java:154)
at hudson.DescriptorExtensionList.load(DescriptorExtensionList.java:182)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:253)
at hudson.ExtensionList.iterator(ExtensionList.java:143)
at org.jenkinsci.plugins.xunit.AliasInitializer.addAliases(AliasInitializer.java:47)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at hudson.init.TaskMethodFinder.invoke(TaskMethodFinder.java:105)
at hudson.init.TaskMethodFinder$TaskImpl.run(TaskMethodFinder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:885)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)