Problems port forwarding a DSL-504G router

Hi,
Am having problems setting up more than one port on our D-Link DSL-504G router.
Can set up one, but need to run uTorrent on another PC, has separate static IP address, etc, but when I try to forward the port I get "Assigned Port Range Overlapped".
It lets me do it if I delete the other port, but when I try to add a second it won't let me.
Have tried as many combinations of port ranges, adding in various orders, etc, but nothing works!
I get the feeling it may be a hardware issue more than anything else, has anyone ever heard of / experienced similar problems?
Cheers