So recently I saw this when doing a svn checkout of a project and ran into the following:
$ svn co http://svn.somewhere.com/svn/projects
svn: Unrecognized format for the relative external URL ”.
Wonderful. This indicated to me there was a problem with the svn externals somewhere. After noodling a little I decided to Google around and found this. Basically, duplicate listings in your svn:externals is a bad thing.
