To solve this delete the svn:special property by doing this:
svn propdel svn:special FILETOCHANGE
You can also use svn proplist FILETOLOOKAT to see the svn properties on that file.
I had just used this script: http://arctic.org/~dean/scripts/unln to unlink but keep a copy of the symlinked file.
Seems to work quite well.
svn propset svn:ignore FOLDERNAME . ^^ Note the dot! More info here
http://sdesmedt.wordpress.com/2006/12/10/how-to-make-subversion-ignore-files-and-folders/
find ./ -name ".svn" | xargs rm -Rf