Hopefully you can help me with the following problem.

I have a Windows XP SP2 desktop and a Vista Ultimate Business
Notebook. Both pc's belong to the same working group: @HOME.
I made the map 'My documents' on the desktop PC 'shared' with
sharename 'My docs' and said that files can be changed.
The IP-adress of the notebook is made 'trusted' in Zonelabs' firewall
on te desktop PC. On both systems I have Office 2007.

Virusscanner on both PC's is NOD32.

Via the notebook I can see the shared map 'My docs' on the desktop. I
can see and open all files (also in the submaps).
On the notebook I also can make changes into the not-Office files in
the shared map, e.g. I can change a JPG-file and save it
under the same name or give it another name on the desktop. However,
if I open an Excel-file, I can change it, but after pushing on
'SAVE' (or SAVE AS with the same filename or with another name on the
desktop), I get the result 'File is not saved' without referring to a
faultcode.

Do you know the solution for this problem?