VNC connections always connection timed out: 10060

I have 2 PCs in my office. We will VPN first and then VNC to the specfic PC. The problem with the 1st PC is that it can VPN to the other party firewall but is not able to VNC. The 2nd PC in my office has no problems, can VPN and VNC. Windows firewall is off. Have try uninstalling ang reinstalling the softwares but still unsuccessful. Both are running Win XP pack 2.