I'm having a problem with dcc. I can have one downloading and finish fine but anything more than one, or I should say downloading more than 1 file at a time is impossible. Connection wise everything checks out and the firewall is properly configured. Mirc's options are set correctly and, well I'm stumped. Does anyone have any ideas?

Note: Can't have more than one download even from different servers.
Mirc 6.16
Winxp sp2
I even tried patching the tcpip.sys file to allow more connections but that didn't do a thing.
Could this be an isp "feature"?