Jenkins 1.597 changed the build ID from being a timestamp to being the build number.

xvfb-plugin calls Hudson.FilePath.createTempDir() using the build ID as the prefix. The prefix must be at least 3 characters long or there is an exception. For builds with the build number < 100, therefore, the build ID won't be big enough and so will fail the build. Sample stack trace below.

An ugly workaround would be to keep running the failing builds until you get to build 100, where it should again be successful.

ERROR: Processing failed due to a bug in the code. Please report this to jenkinsci-users@googlegroups.com
java.lang.IllegalArgumentException: Prefix string too short
at java.io.File.createTempFile0(File.java:1844)
at java.io.File.createTempFile(File.java:1934)
at hudson.FilePath$18.invoke(FilePath.java:1404)
at hudson.FilePath$18.invoke(FilePath.java:1401)
at hudson.FilePath.act(FilePath.java:989)
at hudson.FilePath.act(FilePath.java:967)
at hudson.FilePath.createTempDir(FilePath.java:1401)
at org.jenkinsci.plugins.xvfb.XvfbBuildWrapper.launchXvfb(XvfbBuildWrapper.java:484)
at org.jenkinsci.plugins.xvfb.XvfbBuildWrapper.setUp(XvfbBuildWrapper.java:594)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:655)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:533)
at hudson.model.Run.execute(Run.java:1718)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:531)
at hudson.model.ResourceController.execute(ResourceController.java:89)
at hudson.model.Executor.run(Executor.java:240)