Trouble uploading Photos from Vista PC to iPad

I have both Win 7 and Vista PCs. The Win 7 PC can connect and upload photos to my iPad just fine. The Vista PC can connect but when I upload it just sits there. The app is running on the iPad and I see the little working icon next to the WiFi so it is communicating but choking on something. I have reset the iPad and rebooted the Vista PC, tried both IE8 and Firefox 3.5 as well as disabling the Symantec Endpoint Protection firewall (which is also running on Win 7 PC). Downloading from the iPad works but I can't figure out what could be blocking the upload. Any ideas?