OK, it sounds to me as if you are using Word 2007, and there are problems in
this general area with certain types of data source (e.g. .docx documents).
However, when you create an Office Address List (OAL) in Word's MailMerge
facility, at a certain point you do have to save it (it's a .mdb file). I
wonder if the .mdb is being saved to the network? Obviously if it is being
saved to a local drive, or perhaps to the default folder, which is "My Data
Sources" under the user's Documents folder, and would also be inaccessible
by other users even if the creating user's folders are located on the
network.
Here, Mail Merge Main documents attached to OALs on the network open without
problems (i.e. you see the usual question about SQL). I am using Vista 64
SP1 with Word 2007 SP1 attached to a Windows 2003 server. I don't think the
fact that both are SP1 is relevant but is is possible. I also do not have
problems connecting to an Excel data source.
Finally, there are always two general (potential) problems when using data
sources on the network
a. the users do not have the necessary permissions to access the data
source (this is a tricky area which I cannot say I fully understand)
b. if you use drive letters that are mapped to network shares, you have to
map to the same shares using the same letters on all the user PCs.