can't set .jpg MetaData over network

I have two WinXP-pro SR/2 machines connected by hardwired Ethernet.
A scanner is connected to one;
a hard drive to hold files is connected to the other.
Directory on hard drive is marked for simple file sharing and
authorizing other network users to change files.

Files created by the scanner can be saved to hard drive without problem.
Once saved, they can be renamed without problem. However...

MetaData on .jpg files cannot be edited / added from first machine with
the scanner, although once metadata is added to the .jpg files via the
second machine containing the hard drive, the metadata can be displayed
on the first machine with the scanner.

Is this limited metadata labeling capability normal?

WindsurferLA