Upload problems..

Hi,

Please let me know if there is a solution for this issue.

Couple of months back i had no problems with the wireless speed, but now from couple of days i started having the problem.
Iam unable to upload any files via email thru yahoo/gmail and when i try the speed test from this website (
http://www.auditmypc.com/internet-speed-test.asp )

download shows close to 4816 kbps but for Upload it gives a error saying client cannot send/recieve packets to the server port 8600.

Upload and internet work fine when connected via wired netwrk.
Is there a problem with the wireless adapter, or router?? but others who use the same connection dont have any problems.
PLease update.

Thanks,