There are many things that can affect your GPS reception. As always you will have to be outdoors with a clear view of the sky. You will also want to make sure that the Infrared Beam option has been unchecked in the Beam setting of your iPAQ 38XX. Having this on can interfere with the GPS satellite reception and overall performance.
To turn this option off:
1. On the iPAQ go to the Start menu and select Settings.
2. Go to the Connections tab and select Beam.
3. Turn off the option to Receive all incoming beams and tap OK.