When updating from subversion repository using tortoise svn client I get error looking like that:
Could not read chunk size: An existing connection was forci
There is another annoying cause for this error message. It could be your router or your router's firmware.
I had recently upgraded my Linksys WRT110's firmware from version 1.0.02 to 1.0.07 and after that, subversion could no longer add new files to the repository. It could only update existing files. Rolling back to 1.0.02 fixed the problem.
Sources:
Basically, anytime the connection is abruptly dropped, you're going to get this error. Could be a configuration error on Apache, like many of you stated. It could also be due to a slow server or overloaded connection, or it could be due to a cheap router, as was in my case.