Assuming each user has a regular version of Access (as opposed to the
runtime version), and you've distributed an MDB (as opposed to an MDE), go
into the VB Editor and select Tools | References. Examine all of the
selected References (the ones at the top with check marks beside them).
If any of the selected references have "MISSING:" in front of them, unselect
it/them, and back out of the dialog. If you really need the reference(s) you
just unselected (you can tell by going to the Debug menu and doing a
Compile), go back in and reselect it/them.
If none have "MISSING:", select an additional reference at random, back out
of the dialog, then go back in and unselect the reference you just added. If
that doesn't solve the problem, try to unselect as many of the selected
references as you can (Access may not let you unselect them all), back out
of the dialog, then go back in and reselect the references you just
unselected.
NOTE: write down what the references are before you delete them, because
they'll be in a different order when you go back in
If you are using an MDE, or you are using the runtime version of Access,
check the suggestion I make at
http://www.accessmvp.com/DJSteele/AccessReferenceErrors.html