I am a new iPhone developer using the latest iPhone SDK.
Alas, the iPhone SDK is covered by an NDA, so we can't discuss it
on this public mailing list.
The answer probably lies in the fact that Apple doesn't like you to
do networking programms because you could do evil programs like VoIP
over GPRS/EDGE or even UMTS/HSPA one day (if rumours come true).
Those are "forbidden" Applications.
So either its a very simple error from your part like linking the
wrong one (the simulator might not have the functionality) or its
more political than anything else.
And yes, the above statement is not violating any NDA as I have
never signed one for the iPhone SDK.
In general, if you don't know the answer, it's probably best to just
say nothing so you don't look stupid.