[Lara]

I had a similar problem a while ago and it turned out that the Word document
only remembered the link to one user at the time e.g. when user 1 established
the link, user 2,3,4 (on different workstations)... lost it and for user 2 to
establish it meant all others in turn lost it.

If I remember rightly I gave each user their own copy of the mail merge
document as well as the data to be merged.

The latter can be done via a make table query (or a combination of delete
query and append query on a specifically designed table if you don't want to
loose formatting of fields) to get the data from the server onto the Front
End portion of the DB on each workstation (assuming that not everyone uses
the Front End from the Server)

This way the data gets pulled from the server every time you run a mail
merge and the link just stays the same for each user.

It might also help by using ODBC links instead of DDE but not 100% sure and
I can't test it for you currently as I am not onsite...
Hope this helps