Could you tell us the brand name & model number of your modem-router. The reason is because many broadband modems use nat which is a type of firewall. Whilst some allow LW partial access, some don't allow any access. After LW has been running for 30 - 60 mins can you do this test for us: Bug Report instructions & sample image And tell us whether your results are True or False. If false, then you may need to forward a port to allow LW 100% access.
Also check yur firewalls so they allow LW & java full access: http://www.limewire.com/english/content/firewalls.shtml