Some Wireless will work while others will not?

Hello,

I am currently running a small network (22 computers) in our barraks in Iraq. We are using 2 D-Link DIR-615 routers set up as access points coming off a Hughes HX50 modem/router.
Right now I have several computers that although they register as conected to the network,(I can see them on the network with network magic) the IE 7 browser will not surf the internet.
Thanks, Mike