After LW's been on for at least 30 mins do this test:
Bug Report instructions & sample image Is it True/False?
If it's false then there's a firewall somewhere blocking incoming. Double-check your firewall settings here:
http://www.limewire.com/english/content/firewalls.shtml
Can you tell us your Modem & router brand name & model numbers?
It apparently makes it easier to DC if you both have Chat enabled. Tools>Options>Chat