Is Brighthouse an affiliate of Road Runner?
You may need to remove your old LW 4 firewall exception & re-add LW 5 to Trend Micro as an exception for both UDP & TCP. Make sure Win XP's firewall is not turned on.
I use a Belkin myself but not the wireless version. Mine works generally ok in UPnP mode but after it's been on for a long session starts having issues with apparent communication issues between LW & the router & UPnP starting to struggle. Running in wireless mode is less reliable.

If you wish to downgrade to LW 4, you should see this: http://www.gnutellaforums.com/window...lw-4-18-a.html (if downgrading from LW 5, we'd recommend LW 4.16 instead of 4.18)