iChat file transfer problem with Google Chat

[doobs]

I cannot transfer a picture using a Google Chat account in iChat. The file transfer window shows the picture as "preparing...". Also, I can see that someone outside my home network has sent a picture, but file transfer window shows 0 bytes received. I have a Netgear wireless router with the following ports open, as stated on Apple's iChat documentation website: 5060(UDP), 5190(TCP/UDP), 5297(UDP), 5298(TCP/UDP), 5353(UDP), 5678(UDP), 16384-16403(UDP), 5220(TCP), 5222(TCP), 5223(TCP). The file transfers just seem to never be sent, even when I allow all traffic on my OS X 10.5 firewall. Both the recipient and me have Receive files and Send files in our IM capabilites list. Also, the recipient seems to be able to send files to others. So it seems to be my router or computer. Any ideas? Thanks in advance...