ARD sees remote computer but won't connect

I previously used ARD 2 to connect to my Mom's Mac and all worked well. She recently had to replace her router due to a bad power supply and during that time frame I also upgraded to ARD 3. Ever since I have been unable to gain access to her computer. (I did install the ARD 3 client for her.)
If I'm at her house and connected to her router with my laptop I can gain access, but if I'm at home I cannot.

I checked the port forwarding settings on her router last night and both ports 5900 and 3283 were set to "both". In addition I read where ARD uses port 5988 so I turned forwarding on there as well. When I got home I was still unable to get to her computer.

I'd used DynDNS since she's on DSL and doesn't have a static IP. When I try to connect using the DynDNS hostname it shows up in the ARD scanner, but the IP address is not what her computer is using at the time. I went to WhatIsMyIP.com to get the actual IP address she was using and I can enter that and her computer name will show up in the ARD list so it is seeing her computer is out there, but when I try to connect to it the connection fails. I tried removing her from ARD and re-adding and that didn't help either. I also have ARD on my work computer and am unable to access her computer from there so I don't think the problem is on my home network.

Any ideas on what I might be missing here? I don't know whether this had to do with the router change or the ARD update. I only get in to her house periodically and would like to get this resolved so I can help her when she has computer problems. Thanks!