In case one would care, last time I did the following: bring up Zaurus manager, set back the communication protocol to USBIO. Press OK. Bring up the same program from the second time, set the communication protocol to TCP/IP. Now the NDIS5 driver should be reinstalled.
Note: I did quite a few times of install/reinstall/remove kind of things before eventually hitting at this solution myself. If you can\'t use the sequence I mentioned above, try uninstalling the driver, re-installing it, then do what I did above. Unfortunately I can\'t find a way that\'s less magical (\"unexplainable why\") than these steps. :-( :-(