Unable to commit to Subversion

Question

I have a client who had to rebuild his automated build server. He checked out his project folder from my subversion server but is now no longer able to commit - he gets this err

Answer 1

I did a one vote up for @DamianM answer. In my case it seems that had been the problem. File Corruption which made it not possible to write on server. Issue with SVN Commit for certain File Extension

But Instead of restarting your svn server process / reboot server I copied the dlls[files with problem] again to working folder and was able to commit.