WLAN/WUDFRd issue

I mistakenly posted this problem in hardware instead of software, sorry for the cross post.

I run a small computer lab of 10 Dell Lattitude E6500s running Windows 7 x 64 Enterprise. They connect to a ZyXEL ZyWALL 2WG for internet/network access.

I have a recurring problem on all the machines (they are virtually identical in terms of OS, software and configuration). Randomly anyone of the computers will drop off the network.

I looked into the event log and I see the same recurring series of errors/warnings on all the machines.

First I get a "WLAN Extensibility Module has stopped. Module Path: C:\Windows\System32\bcmihvsrv64.dll" 10002 warning from WLAN-AutoConfig. Then I get a "WLAN AutoConfig service has successfully stopped." 4001 warning from WLAN-AutoConfig. Then finally I get a "The driver \Driver\WUDFRd failed to load for the device USB\VID_0A5C&PID_5800&MI_01\6&66de6c9&0&0001." 219 warning from Kernel-PnP.

bcmihvsrv64.dll (Broadcom Independent Hardware Vender Service 64) is part of the driver for the wireless adapter and 6&66de6c9&0&0001 is a reference to my smart card reader.

Before I checked the Event Viewer I thought I might be having a firewall problem, but disabling the fire wall didn't change anything.

I also thought it might be a Network Discovery problem, so I tried turning off the "Computer Browser" service and changing my NetBIOS Over TCP name resolution nodetype to broadcast via regedit.

I have updated the driver for the wireless adapter to the newest version, as well as trying the windows native driver. Subsequently, I have updated the chip set driver and the BIOS.

I don't believe that the problem is with the router or the network setup as I still get the 4001 and 219 warning if the wireless adapter is disabled. This would also suggest that it isn't a driver problem (at least with the wireless device).

I'm out of ideas to try or things to search for and have found only dead ends on google. Dell also has been less than helpful. I'm hoping somebody somewhere has an idea that can fix the situation.

Thanks for your help.