I've had that happen to me before with Access. Unless you are truely doing a very complex query (Access does have its limitations), I would double-check the grammar of your query. When I got the error before it was usually because of something I missed or did wrong in the query. i.e. although it was syntactically correct, a missing operand/join/etc made the query appear too complex to Access.
Blake Minghelli<br />SCWCD<br /> <br />"I'd put a quote here but I'm a non-conformist"
Does the query work when you run it in Access? If not, consider posting the SQL here. If you do, it might be helpful to have some details about the tables: primary key fields, table relationships, etc.