samba - Jan 2006 - Any ESRI users? Upgrade 3.0.14 to 3.0.21a broke Arcmap layer loading?

We just upgraded our samba server from 3.0.14 to 3.0.21a and have discovered
a subtle but very painful problem.
Users of ESRI ArcMap (on fully patched Windows XP clients) are unable to
read complex layered file data.

Arcmap works fine with 3.0.14, it works fine with the data on a windows
share, and it works fine when I set up a server to run the version of samba
shipping with Solaris 9 (3.0.2! ). But, I really don't want to downgrade the
primary file server to one of these old versions. The data also works fine
if it is copied back from the Samba server to a local disk.

The problem as I understand it is that ArcMap loads ".lyr" and
".mxd" files
which in turn contain metadata that references multiple other files. When
these secondary files are loaded from the Samba 3.0.21a server, they are
opened but not fully read - the database files show empty fields, the maps
show partial images, etc. To quote our GIS guy: "arcmap documents that have
nested layer references to data on SAMBA, and also compressed shape (.sdc)
files such as are included on the esri maps and data cds (if they happen to
be on aSAMBA share, either cause arcmap to crash, or appear in the table of
contents as layers that have no records."

The windows XP event viewer shows an error when this happens:
MRxSmb  Description: The redirector failed to determine the connection type
http://support.microsoft.com/kb/315244/

 I'm not seeing any particular errors on the server side  (although I am
getting some of these: https://bugzilla.samba.org/show_bug.cgi?id=3346
<https://bugzilla.samba.org/show_bug.cgi?id=3346>i'll be glad to see
3.0.21b)

ESRI claims to have no knowledge of the problem, and since their software
works OK with other Samba versions they feel it isn't at their end.

Are there other ArcMap users here? Any thoughts on what to pursue next?
(other than installing 3.0.21b at the first opportunity)

thanks Betsy