Try here for that answer
Q. The WI-FI adapter is not listed in the "Choose Adapter" of the properties.
A. The iPAQ models that have built-in WI-FI may have a corrupted registry entry:
HKEY_LOCAL_MACHINE /Comm/vnetmini
Has:
Linkage\Route (data: unreadable.dll)
should read:
Linkage\Route vnetmini1
You'll need a registry editor to correct the problem.

Also see
http://www.ndis.com/faq/QA01190301.htm regarding promiscuous mode and WI-FI.
Q. I get an error "cannot load driver" when attempting to run vxSniffer on a Pocket PC 2003.
A. It appears the incorrect version of vxSniffer was installed on your HPC (most likely the Pocket PC 3.0 version)
Do the following:
1. Remove vxSniffer
2. Copy the file vxSniffer.ppc42_arm.CAB from the desktop to the HPC
3. Double tap the file copied in #2 above on the HPC
4. It will install
Seek