If you want to use Eclipse SVN plugin under a proxy, “server” file must be configured. The file is located in %APPDATA%/Subversion.
Uncomment the following lines:
#http-proxy-host=proxy1.some-domain-name.com
#http-proxy-port=80
#http-proxy-username=blah
#http-proxy-password=doubleblah
#http-timeout=60
Keep in mind that spaces are not allowed.