samba - Jan 2001 - samba, vfat partitions and office 2000: read-only problem

I used to share a vfat mounted partition with other collegues through samba. 
Everithing works fine with my old notebook (Mandrake 7.2) but my new notebook 
(Mandrake 7.3 beta) seems to have problems even if I use the same version of 
samba (2.0.7) and the same smb.conf file. 
Through samba I am able to share directories of a linux partition without any 
problem but if a share a directory which is part of a vfat mounted partition 
I have problems with office 2000 applications. They are not able to save the 
file, as if it was read-only. Similar problems do not affect notepad or other 
windows applications. As I said I am using samba 2.0.7 under Linux 2.4.0 
(glibc 2.2) while the clients are win98se machines. I imagine the problems is 
related to locking and/or permissions but I cannot find any solution.

Any help is gretly appreciated (please reply directly to me, also, if 
possible, since I do not access the samba mailing list frequently).

Regards
  G.