It's just a general cannot connect error. It indicates some socket level error. It should be trivial to debug if you wrote decent code.
A few ideas:
a.) Personal firewall
b.) Real firewall or other network configuration issue (routing)
c.) Is there more than one network adapter in the problematic PC? If so, what's the binding order?
d.) Typo? Trying to connect to the wrong host
Also: This should be in the Application area since it has nothing to do with the 3300. Maybe Chak can move us?
