Vista - office save as error

hello,
I have 2 new Acer 6592 Vista (business) notebooks on domain (and many others
with
WinXP) with Windows 2000 domain controler.
When I want to "Save as" a file from Word 2007 (Office 2007 prof. plus) to
file server disk, it is
impossible to create new subfolder by this way. It notices, that parent
folder is "unreachable" (sorry, maybe it is not correct translate notice to
English, I have Czech Vistas), but the standard name "New folder" is
created, file is not saved (parent directory notice, again). When I tried
the same with notepad, I cannot create new subfolder, but I save the file
;o).
(I tried switch off UAC, I tried the same as a domain admin, administrator,
but it works not too).
I have seen the same problem on external USB disks in the same moment, but
on that disks the problem disapeared next day.
Persists on network.
But no help in network forum.

When I try to create folder from Total Commander it works fine, all
operatins work normally. My own HP6710b with Vista Business and Office 2007
(not plus) works fine in these situations.

Thank you for any help.
--
Regards, Jiri Cvrk
http://cvrk.com/indexe.htm