Does it freeze when you keep the Orinoco silver card out of the unit? How about when you run the Ipaq "naked" (without the PC card sleeve)? Do you have any Today Screen plug-ins that look for storage cards, etc..?

Run iTask and close all your programs (or better go to Settings, System tab, memory, running programs and end all there.) Unload any Today Screen plug-ins that might be suspect, and then try MiniStumbler.