Which version of Word/Access are you using, and did you upgrade around April
2003?

If you are using Word XP or later, by default WOrd uses OLEDB to connect to
your Access databases and some types of query can not be used, including (I
think):
a. Parameter queries
b. Union queries
c. queries that use user-defined Access VBA functions
d. queries that use some built-in VBA functions
e. in some cases, queries that use wildcards (*,? etc.) in comparison
statements

In the case of (e) in particular, the problem is that Access (or specific
databases) may be set to use one wildcard convention whereas Word is
expecting to use another, and the two will not work together.

A workaround for most of these problems is to revert to the connection
method used by default in Word 2000 (DDE)  - in WOrd XP, check
Tools|Options|General|"Confirm conversions at open", go through the data
source selection process again, and select the DDE option when offered.

--
Peter Jamieson
MS Word MVP