opening ports for itunes home sharing

I initially posted this on the iTunes form, but it should have probably been posted her.

Home sharing was working great between 2 of my macs until either I (1) installed a new wired linksys router or (2) installed a new imac for one of my previous macs. I'm not sure which, if either of these changes have created my connection problem w/ iTunes Home Sharing.

Sharing and pinging works between both computers except in home sharing. I have verified that sharing is turned on, itunes sharing is on, home sharing is on, both computers are registered in home sharing to the same itunes account.

I am unable to get a connection between the 2 computers for the home sharing (the home sharing icon on the left itunes menu just disappears) or for the general itunes sharing. In itunes>prefs>sharing the status on both computers shows "OK, no users connected".

Following is what I've tried to resolve this problem:

1. Gone into my new router and forwarded ports 3689 and 5353 for both computers.

2. Turned firewall on and off but of no help.

3. When I run a port scan on my computer, it shows port 3689 open but no mention of port 5353.

4. On my wife's new iMac neither port 3689 or 5353 show as open.

If the opening of ports is the problem, how can I go about getting them open? As stated above, I've forwarded the ports in my LynkSys router.

If open ports isn't the problem, what else could I try?