I get the following error at startup:

hudson.util.IOException2: : only whitespace content allowed before start tag
and not n (position: START_DOCUMENT seen n... @1:1)
at hudson.XmlFile.unmarshal(XmlFile.java:150)
at hudson.model.Run.<init>(Run.java:251)
at hudson.model.AbstractBuild.<init>(AbstractBuild.java:150)
at hudson.maven.AbstractMavenBuild.<init>(AbstractMavenBuild.java:58)
at hudson.maven.MavenBuild.<init>(MavenBuild.java:95)
at sun.reflect.GeneratedConstructorAccessor18.newInstance(Unknown Source)
at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at hudson.model.AbstractProject.loadBuild(AbstractProject.java:807)
at hudson.model.AbstractProject$1.create(AbstractProject.java:209)
at hudson.model.AbstractProject$1.create(AbstractProject.java:207)
at hudson.model.RunMap.load(RunMap.java:221)
at hudson.model.AbstractProject.onLoad(AbstractProject.java:207)
at hudson.maven.MavenModule.onLoad(MavenModule.java:197)
at hudson.model.Items.load(Items.java:107)
at hudson.model.ItemGroupMixIn.loadChildren(ItemGroupMixIn.java:58)
at hudson.maven.MavenModuleSet.onLoad(MavenModuleSet.java:405)
at hudson.model.Items.load(Items.java:107)
at hudson.model.Hudson$9.call(Hudson.java:2036)
at hudson.model.Hudson$9.call(Hudson.java:2029)
at java.util.concurrent.FutureTask$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: com.thoughtworks.xstream.io.StreamException: : only whitespace
content allowed before start tag and not n (position: START_DOCUMENT seen n...
@1:1)
at
com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:78)
at
com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:154)
at
com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:147)
at
com.thoughtworks.xstream.io.xml.AbstractPullReader.move(AbstractPullReader.java:126)
at
com.thoughtworks.xstream.io.xml.AbstractPullReader.moveDown(AbstractPullReader.java:111)
at com.thoughtworks.xstream.io.xml.XppReader.<init>(XppReader.java:48)
at com.thoughtworks.xstream.io.xml.XppReader.<init>(XppReader.java:36)
at hudson.XmlFile.unmarshal(XmlFile.java:148)
... 24 more
Caused by: org.xmlpull.v1.XmlPullParserException: only whitespace content
allowed before start tag and not n (position: START_DOCUMENT seen n... @1:1)
at org.xmlpull.mxp1.MXParser.parseProlog(MXParser.java:1519)
at org.xmlpull.mxp1.MXParser.nextImpl(MXParser.java:1395)
at org.xmlpull.mxp1.MXParser.next(MXParser.java:1093)
at
com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:63)
... 31 more

Unfortunatly it doesn't log, which file is broken, so i can't check the file and
fix it.