Go through the sticky at the top of this page, the first part "... check here first". Make sure your firewall's configured properly. Do the port test & see what result you get. Read the info about internal firewalls within routers, does your router have one?

What are your details

OS(Win XP etc)
LW & Java version (help > about LW & you'll see)
Firewall you're using
Modem/router brand & model
ISP
Connection type (DSL etc)
Where you connect from (home, school etc)
Are you sharing a connection with other computers
Is this your first try with LW

Within LW, go tools > options > bug reports > view example. Scroll down to 'recieved incoming this session'. Is it true or false?

Please don't double post.