http tunneling not supported

[Craig_Reichenbach]

Hi, I'm new to CVS & trying to use it to connect to a CVS repository at
sourceforge.net.  I am behind a firewall at work and have WinCVS set to use
my company proxy.  I receive an error message that the proxy server "does
not support http tunnelling".  I haven't found anything about this problem
in the archives or cvs site faq.  Can someone please point me in the right
direction?

Thanks,
Craig