Never seen that, and I just checked (Linksys here)... refreshing the application list goes to port 80, same as http/web browsing. So it shouldn't be a port-blocking issue.

Since your web browsing works, I'm hesitant to suggest even trying this because it is so unliikely... but it is one thing that does effect performance between different routers. In OS2008 you can easily change the Wi-Fi Power Saving Mode. Go into your tablet Wi-Fi connection and in the Advanced options you'll see a drop-down list to choose the PSM. Try none, and see if that helps.