What's the make and model of that router?
There this sithe that will help you out.
You also need to make sure taht your modem isn't working as a router. For instance a 2 wire or a verizon fios "Modem"....These also have DHCP and if it's giving out private ip's then it needs to be port forwarded too.
I am new to this but here goes.
I had my slingbox solo connected to Sky broadband with no issues, yesterday I had Virgin Media installed, guess what can't get it to work.
I enabled port fowarding on 5001 in the new router yet it still will not configure and says poor internet connection, I did a speed test and it was well over 30meg.