Not sure what the loss of functionality is, but probably isn't good:

Apr 25, 2012 3:01:13 PM hudson.ExtensionFinder$GuiceFinder$SezpozModule configure
WARNING: Failed to load hudson.plugins.emma.portlet.chart.EmmaBuilderTrendChart$DescriptorImpl
java.lang.LinkageError: Failed to resolve class hudson.plugins.emma.portlet.chart.EmmaBuilderTrendChart$DescriptorImpl
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.resolve(ExtensionFinder.java:467)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.configure(ExtensionFinder.java:485)
at com.google.inject.AbstractModule.configure(AbstractModule.java:62)
at com.google.inject.spi.Elements$RecordingBinder.install(Elements.java:229)
at com.google.inject.spi.Elements.getElements(Elements.java:103)
at com.google.inject.internal.InjectorShell$Builder.build(InjectorShell.java:136)
at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:104)
at com.google.inject.Guice.createInjector(Guice.java:94)
at com.google.inject.Guice.createInjector(Guice.java:71)
at hudson.ExtensionFinder$GuiceFinder.<init>(ExtensionFinder.java:280)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at net.java.sezpoz.IndexItem.instance(IndexItem.java:181)
at hudson.ExtensionFinder$Sezpoz._find(ExtensionFinder.java:616)
at hudson.ExtensionFinder$Sezpoz.find(ExtensionFinder.java:591)
at hudson.ExtensionFinder._find(ExtensionFinder.java:149)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:289)
at hudson.ExtensionList.load(ExtensionList.java:278)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:231)
at hudson.ExtensionList.iterator(ExtensionList.java:138)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:282)
at hudson.ExtensionList.load(ExtensionList.java:278)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:231)
at hudson.ExtensionList.iterator(ExtensionList.java:138)
at jenkins.model.Jenkins.getDescriptor(Jenkins.java:1060)
at hudson.plugins.disk_usage.DiskUsageProperty.transitionAuth(DiskUsageProperty.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at hudson.init.InitializerFinder.invoke(InitializerFinder.java:120)
at hudson.init.InitializerFinder$TaskImpl.run(InitializerFinder.java:184)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
at jenkins.model.Jenkins$6.runTask(Jenkins.java:838)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
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:662)
Caused by: java.lang.TypeNotPresentException: Type hudson.plugins.view.dashboard.DashboardPortlet not present
at sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:98)
at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:107)
at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:31)
at sun.reflect.generics.visitor.Reifier.reifyTypeArguments(Reifier.java:50)
at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:120)
at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:31)
at sun.reflect.generics.repository.ClassRepository.getSuperclass(ClassRepository.java:66)
at java.lang.Class.getGenericSuperclass(Class.java:677)
at hudson.ExtensionFinder$GuiceFinder$SezpozModule.resolve(ExtensionFinder.java:458)
... 42 more
Caused by: java.lang.ClassNotFoundException: hudson.plugins.view.dashboard.DashboardPortlet
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:95)
... 50 more