AirPort perplexed

I have the following situation and I am really at a loss for a solution.

Here are the details.

Running an AirPort Extreme with 802.11n (version 7.3.1) also compatible with b/g

Other settings:
WPA/WPA2 Personal
Multicast rate of 2mpbs
I am using interference robustness option
IPv6 mode is blocking incoming connections and it is configured automatically
IPv4 is using DHCP

AirPort itself is connected to Ethernet.

So here is the kicker...

My computer is running Tiger (10.4.11) and my connection keeps breaking down. AirPort on my computer always keeps showing strong signal and says that it is ON, but the connection breaks down for large periods of time. For example, my MSN, Skype or Google Notifier shut down and show loss of connection.
My firewall is on as well.

So what makes this confusing?
1. I can access the same internet connection on my PC laptop (Windows XP) at all times while the Mac is having problems

2. My roommate with an iMac running Leopard can also access internet off the same network while I am having problems.

I've tried running diagnostics... no luck. I've looked for viruses with Norton Antivirus and there don't seem to be any traces of an infection...


SUGGESTIONS ANYONE? Please help!

"connection breaking down"? ... Are you losing your connection to the network? Is the Network disappearing from the Airport menu? or is your signal strength dropping to zero?

Next time you lose your connection, go into your Network Pref's and see if you're getting a valid IP Address from your Extreme.

If the Extreme is working for any other computers at the time of the problem, the issue is with your computer, or you're getting some sort of interference.

Also, what happens if you plug into your Extreme with ethernet?