Thanks for everyone's help.  I found out the problem and the solution.  I
wasn't aware of this and thought it might helpful.

The .LDB file keeps track off record locking and such.  Anyone who wants to
open the database as shared (whether it's read-only or not) must be able to
write to this file.  So i READ-ONLY access to the directory and explicitly
gave WRITE access to that file.

As for the security features provided by Access, yes, i would have rather
used that, but it was quicker and easier (albeit not quite as pretty) to do
it this way.  First of all, i haven't taken the time to familiarize myself
with Access's security features (i'm a network admin, not a programmer).
Also, i assum there is something involved on the client side that i'd have
to do for each person using it, and i didn't enjoy the idea of making the
changes 200 times.

Thanks again for everyone's help.