Ok problem has been solved, you need a reserved IP in the LAN setup to do any port forwarding. I suggest that in the error message, it is better defined as 'IP is invalid' does not help the user create the rule, and point to the issue.
I should note, Ive been able to have port forwarding rules on dynamically assigned IP's in like... basic Netgear OS so it may be good to have the option to pair it to MAC or something in the future.