Excel RO with Vista Client

Hi - We have a server NW6.5. And I've just setup a new laptop Dell, with Windows Vista. We have a problem to open files on the server, and its the same when connected as .admin

We have
Windows Vista Ultimate
Novell Client for Vista SP1
Office 2000.

The first excel file i open from the server, open's with no problem. Then I try a second file, and that claims to want to open as 'Read-Only'. Not good. If I cancel that and try it again, the file opens fine. Same for the third file, fourth etc... 1st time read-only, you cancel and then you can open it fine...

Any ideas?