Here's your problem RIGHT HERE!

OK, I now have 12 hours into playing hard core (Engineering, not games) with this router. Since the D-Link tech support has their heads buried the same as the ones at Linksys/Cisco did. I have tried every Firmware from 1.21-1.34NA (my hardware is A4). As far as bricking your router from downgrading, you have about the same chance as bricking it from upgrading. They just set a couple of "write bits" in the software so you can't put in the older stuff, but the Russians took care of that. This is the same thing Motorola tells us on police/commercial VHF radios, if I had a nickel for every Motorola radio and cellphone I have modded with software, I would be able to pay for a OC-3 line to my home! Never have bricked a one, except the one I dropped in the pool!
Everything works fine with this router on 1.34NA, for the most part, UNTIL that is you turn on wireless security.

You can use WEP just fine, over a 45 minute period I had ZERO problems on 54G with WEP, BUT,, as soon as you turn on WPA or WPA-2, your problems begin! I have it running on a plotter right now to calculate the drop timing. WHATEVER you do, DON'T enable AUTO WPA, it seems to make it drop twice as much, pick one, WPA or WPA-2. So where does this leave us, since the wireless "N" standard does NOT support WEP, you have to run in either no protection from prying eyes or deal with the wireless drops. If you run B or G modes, you at least have WEP to somewhat secure your computer from wardrivers.
As I said before, I am an Electronics Engineer with over 20 years experience in the USA, lost my EE work to India, so now I just can't help but criticize their SLOPPY work and the need for 20 revisions to get it right, this is NOT Amateur hour! Leave the Engineering to the real Engineers!
Adjust the setting in your router at your OWN risk, I will not be held responsible for a bricked router. Also, your mileage MAY vary depending on a lot of factors that are inherent to RF communications that most people don't usually consider.
I also find a lot of newer electronics from the same run don't act the same when your using them. We have ROHS and the Europeans to thank for ROHS, now we have to use solder that has a melting/flow point 200 degrees F hotter then we used to, thus we are over cooking the electronic chips and making chips from the same lot have slightly different characteristics depending on how much heat damage each chip sustained during manufacturing.
I hope this helps someone else!
Pat