This error message can show up when updating/commiting/checkingout project from svn repository. The reason can be different for different repositories. So, for clarity I have described some details about my svn repository.
General CauseThe 500 Internal Server Error is a very general HTTP status code that means something has gone wrong on the web site's server but the server could not be more specific on what the exact problem is.
My Repository SetupI manage/communicate to svn repository through HTTP protocol. So, every request is handled through apache web server. User authentication is done using simple htpasswd file.
DebuggingAs this is an internal server problem, the best way to debug this is to look at the server error.log file. This is what I found when I checked the error log of apache web server.
[Tue Jul 07 08:58:33 2009] [error] [client xx.xx.xxx.xxx] (13)Permission denied: Could not open password file: /home/myusername/svn/project.passwd
My FixFrom the apache error log, it was clearly visible that the web server was not able to read the htpasswd file to verify users. So, I changed the file permissions so that the web server can have READ access to my htpasswd file.
Hope this helps. Good Luck