running out of sockets...

[John Windberg]

I'm writing client code against Autodesk Vault web
services which are .Net code within an IIS instance.
After a series of calls I start getting "out of
sockets" or "access denied" errors, which seem to be
caused because IIS on this XP instance has a limited
number of available connections.
I'm only calling one at a time. Why would my
connections not be getting closed?