Subversion Commit Problem: XML data was not well-formed

Finally, I figured out that redefined ErrorDocument in .htaccess file for the same VirtualHost as the SVN's caused invalid data to be sent to SVN client on some occasions and for some reason intercepting with commit process.

While in theory it would be educational to figure out problems like this, life is too short and i'm already expert at other things, for which i'm being paid to be expert at, so my fallback solution to any svn trouble is this: go outside of the working copy, make a new directory somewhere else, make a fresh checkout of whatever branch from the repository, and then manually update the files you know you've changed, by copying from the messed-up checkout.

As for apache, i'd bet it's innocent of any trouble. Failed commits are almost always due to something other than the connection to the repository. (Assuming no one was tinkering with apache or the svn server.) No guarantee, but trying the fresh-checkout and manual copying over of files may just work, or at least reveal new diagnostic information.

Daren, you are not exactly correct right now. I've tried all the possible combinations of working copies, new repositories and so on. I've tried mostly everything. At last, I've found one strange message in NEON debug messages, displaying my 404 page on a homepage, which I mostly forgot about. Then, I've realized - as created long time ago - I've sent improper HTTP status code from the 404 page (200 instead of 404), therefore NEON considered it proper output and processed, leaving it in somehow incorrect state.

So, right now it was apache issue, caused by stupid web developer - me in 2003... :)