Did you configure it to allow LimeWire (LW)? (advisable not to have 2 active firewalls b/c they can interfere with each other); Firewall configuration instructions (click on link)

Do you see a brick wall in front of the blue world icon at the bottom of LW's interface?

Depending on your connection, sometimes if LW is overworked its connection can suffer. At least that's with LW Basic. Using the Resume/Find Sources on too many files at once can have that effect!!!