Enrique,
Do you have a firewall running? If so, try "allowing" traffic with TFW. When it starts, it checks the ProSIM homepage for updates. This may be conflicting with your firewall.
Barring this, if you do not have a broadband internet connection that is always on, you might try dialing into the internet BEFORE starting TFW.
If neither of these things works, please e-mail me at:
pproctor@prosimco.com
and we will troubleshoot further.