How can I change the port used for my router settings?

I am trying to forward port 80 on my router, but I keep getting this error message: The public port number cannot be 80 because it will have a collision with the Wireless Router web service.How can I change the port used for my router settings?
Have you got the router configured to be able to change settings from the outside, and if so is that on Port 80 as well. Might that be your problem?