Haha, I was having trouble with SVN in Netbeans. It was trying to log in with the wrong user. I could checkout fine by editing the tunnel parameters in the checkout window, but after that if I tried updating it’d use my local username instead of the one I use on the server.
After looking around a bit I found the answer!
In the checkout window, when asked for the url of your svn server, add your username to the url twice. so
should do the trick, apparently Netbeans only removes the first username@ from the url. I tested it and it does seem to work.