Remote management router problem~

[skipholiday]

I'm attempting to remotely connect 2 pc's using timbuktu or
tightVnc.
I can connect to both computers remotely if I connect both computers directley to there cable modem.
If I connect them to there router's and put both pc's in the dmz,neither will connect.
I've even tried using dyndns and I have the same problem.Ive tried forwarding the ports for the vnc software and Im still without remote connection.
The router's are a linksys wrt54g and a netgear WGR614.
Xp firewall and the routers firewalls are both turned off.
Any help would be greatley appreciated.

Thank you

 

[skipholiday]

Update: I'm using Charter Cable internet service.If I use the remote software on a local dsl line,it works perfect.I can access the pc (which is also on Charter Cable)without any problems.Anyone have a clue?