"The operation has timed-out"

[SC]

I'm a newie in .net, and here is my problem.

I have a windows application that pass trough a proxy to access a
webservice. I use the following code to set the proxy:

GlobalProxySelection.Select = new WebProxy(new Uri("http://ip:port/"),true);
GlobalProxySelection.Select.Credentials = new NetworkCredential(usr, pass);

Well, the problem is that i get an "The operation has timed-out" error. I
try a lot of different ways to set the globalproxy but always throw the same
error.

What is wrong with that code?

Tks!