You will need to forward a port for your Linksys.
Port 1. Forwarding instructions for the Linksys BEFW11S4 v2 & you will need to set up a static ip & instructions are included with a link on that page.
2. You'll also need to force ip within LW:
Force IP instructions & sample image This should fix up the majority of problems.
3. Updte your Java:
Java 1.4.2 (click on link)
4. IF you still have problems see:
'Some' solutions to SP2 problems & since there's no single answer to SP2 for every one. Do a search of the forum for SP2 for more solutions.