Recently our team source code repository developed a problem. To be fair I don't believe that the problem was with subversion but with a disk fault but the effect was the same - subversion had a problem with one of the revision files.
After talking through the options we thought that we could replay the revisions using the svnadmin dump command and pipe the output into a new repository. Once for all the revisions up to the faulty one and again for those past the problem to HEAD. This did not work the receiving repository did not like having discontinuous build numbers.
I tried various utilities that reported they could fix fsfs format svn databases but non found or fixed the problem.
I ended up copying the previous revision over the faulty one - giving me nightmares about that missing revision. Now time to start digging through the backups for a good version of that file.
If anyone knows of a good tool that can dig into the svn filesystem to allow hand patches of revisions please let me know.