TCP Reset problem

HI!

Let explain my problem. I'm trying to share with my collegue but I'n running in some odd problem. Everything is done F line on both side, C line on both side he has a fix ip and I habe dyndns active, port forwarding is done on both router, as result he can connect to me but I can't .On the firewall logs I can see I'm trying to connect to his ip, but it olways end up with TCP reset....I have ADSL, he has tv cable connection... I have setted as remote management a secial http port on his router but I can't reach eve this...so something is wrong it seems that is taking to long tiome or is not answering at all...Please give me some hints ( the only thing I haven't tryed jet is to deactivate his firewall, but this shoulden't be the solution).

Thanks

Ang69