The external read-only copy on http://code.google.com/p/fieldtrip is synchronized with svnsync in a cron job. If the cron job somehow fails, the following error can result in subsequent synchronization attemtps.
Failed to get lock on destination repos, currently held by 'mentat004.fcdonders.nl:0da489b8-309d-40ed-8676-a68156ec4787' svnsync: Couldn't get lock on destination repos after 10 attempts
To resolve this error, you should run
roboos@mentat004> svn pdel --revprop -r 0 svn:sync-lock https://fieldtrip.googlecode.com/svn/ property 'svn:sync-lock' deleted from repository revision 0