p2p applications not working.

Ok, just to start im pretty much a newbie in this area.
My brother and I were just hooked up to the internet through comcast, he has the main modem in his room and in my room i have a linksys wireless-b network adapter.
Now the problem is ever since its been installed neither me nor my brother can download from p2p apps, ive tried kazaa,soulseek, morpheus, shareaza, ect. i can connect, search for files and it works fine, but when i try to download only 1 out of like 200 files connects and it only dl's at like 1kbps,all the rest say "more sources needed", everyone else i know is not having these types of troubles. downloading from sites gives speeds of about 220kbps, and evertything works perfectly. I called comcast and they dont restric p2p, and theres no firewalls anywhere.
anyone have ANY clue, its pretty frustrating.

 

How are you linking the two computers? Are you linked directly to your bro's comp or is the setup the modem is plugged into a router and the router into both computers?

If it's a router then you most likely just need to open some ports.