If you are behind a funky proxy and SVN checkout prompt returns a “can not connect to the bla bla server” than you should try to modify the ‘servers’ file which is located probably under /etc/subversion
and add the lines below
http-proxy-host = writeyourproxyhere
http-proxy-port = 8080 #writeyourproxyporthere
http-proxy-exceptions = localhost #etc
http-proxy-username = your_user
http-proxy-password = your_password
and let’s hope that it will work.