Shoutbox

I am trying to figure out why my neighbor's daughter can't access her mother's computer via remote assistance through Messenger.  I was able to access the daughter's computer with no problem, but when she tries to access her mother's computer, it comes up with a DNS name error.  Her mom's computer is hooked up to the internet via a cable modem & a Belkin router (the daughter's computer is hooked up directly to the modem).  Does anyone know what needs to be setup in the Belkin router for this to work?  I changed a couple of settings, but they didn't fix the problem.  They are using MAC address filtering, but I don't know if that will stop it or not.  If anyone has any ideas, your input will be greatly appreciated.  Thanks in advance.