This bugged halted a release for a few days due to my unability in fixing it or googling a solution for it, so I thought I might post how I fixed it for other travellers of the net. The bug manifested itself when trying to release a new build and Hudson sput out the following error:
ERROR: Failed to parse POMs
hudson.maven.MavenEmbedder$1: Parse error reading POM. Reason: expected start tag name and not < (position: START_DOCUMENT seen <<... @1:2) for project unknown at /opt/hudson/.hudson/jobs/My HelloWorldProject/workspace/trunk/pom.xml
WTF? I had never seen that error before and neither did Google. It basically says that Maven cannot parse the xml pom file, which is strange considering that it built locally. It turned out quite easy to fix: just delete the workspace in Hudson. I did know anything about Hudson, so it never occurred to me that this was an option, thinking it might corrupt the setup, but the workspace just contains the current code that was checked out.