the problem doesn't seem to be related to the network adapter: I've encountered this problem first with a wireless pcmcia adapter and a wireless Belkin router connected to the USR9105, then I've removed all the wireless hardware, and used a wired connection to the USR9105 via the built-in network adapter of my notebook, but the result remained the same: internet connected, router is up, then when I start Limewire the connection is lost, the WAN IP led on router goes off and it needs to be restarted.