If you connect at 52 KB/s then your connection speed plan is 512 kbps not 256. It is possible to have a bad host. There apparently are some bad ones out there that allow you to connect thru them but then don't give any response back. There's been talk in the past about that.

One thing we haven't mentioned yet is the possibility your isp provider has detected you use p2p softw & has applied a filter upon you or have just generally started using p2p filters. It something many isps are starting to do now b/c p2p uses great amounts of bandwidth which causes major traffic thru the isp.