"Incorrect Function" error when saving to network places

I have a new PC running XP Pro version 5.1, build 2600xpsp_sp2_qfe.
070227-2300: Service Pack 2.

I have set up a bunch of network places. These work just fine in
Windows Explorer, Microsoft Office, and EVERY OTHER APPLICATION except
for Adobe HomeSite+. When I try to save a file in that application, I
get an error "Incorrect function." I have never had this problem
under Windows 2000.

I've seen posts about this error occurring in XP when accessing a CD/
DVD drive, but never accessing a network drive.

Anyone know what the problem could be?