strange ethernet shield problem

ok i have the official Ethernet card and am having some strange problems

I was trying to connect using a linksys wrt54g router with no success. The router is away from my reg computer so I never had them connected at the same time.
So I hook up another router near my home computer and hook them both up at the same time and everything works as it should. Im excited at this point until I unplug my duino from my puter and plug in the barrel jack. Nothing happens none of the tx rx lights come on. So I plug it back into my computer and it works again. I was thinking that there was some issue with my barrel jack not providing enough juice or something but it seems the only way my duino will connect to the router is if it is connected to a computer with the proper drivers. I plugged it into my roomates computer without drivers and it didnt work. When I installed them it did.

What gives here?

I have an Arduino Duemilanove 2009 purchased from adafruit
official wiz net ethernet shield without sd card

thanks

Does your program write to serial? That can lock up if there's nothing attached.

Im excited at this point until I unplug my duino from my puter and plug in the barrel jack.

Without telling what you plug into the barrel jack, the only guess is what was plugged in is not adequate. Something like a 9v battery probably won't work.

Im using the stock ethernet web server sketch. works perfectly when connected to puter with proper drivers

the power is from a wall wart. I dont think its a power issue because it starts to work when the computer it is plugged into has the proper usb drivers.

I am really stumped on this one. I am so glad I figured out the problem though.
I am sure it is something simple.

Once the board is powered up from the wall wart, push the reset button on the board. More info below.

Thanks that was it. Seems the reset button on my shield isnt working