Steve, thanks for the reply
Yup, the UAC bit was a "shot in the dark" I'm afraid.
You did trigger some thoughts on additional testing though, still no Joy
Here's the additional testing:
Created a new user account (non-priveleged) added it to the share with FULL control
TEST FAILED
Booted W7 box in SAFE-MODE with NETWORKING tried several user accounts
TESTS FAILED
Here is what is shown by net share on my w7 Ultimate
C:\Windows\system32>net share foo
Share name foo
Path C:\foo
Remark
Maximum users No limit
Users
Caching Manual caching of documents
Permission Everyone, FULL
BUILTIN\Administrators, FULL
rob-HP\bkup, FULL
another W7 share on W7-Pro
C:\Windows\system32>net share mp3
Share name mp3
Path C:\mp3
Remark
Maximum users No limit
Users
Caching Manual caching of documents
Permission Everyone, FULL
BUILTIN\Administrators, FULL
Gator\Guest, FULL