Only fails when logging is off

Here is a problem that disappears when logging is on:
Attempting to issue the following SQL query from Access '97 against a postgres database:

SELECT tcompanies.company_id, CStr([tcompanies].[login_id]) & ": " & [tcompanies].[name] AS Expr1, tcompanies.name
FROM tcompanies
WHERE tcompanies.active
ORDER BY tcompanies.name;

column 'active' is boolean

2 messages ppear in succession
1. ODBC Call failed
2. ERROR: Unable to identify an operator "=" for types "boolean" and "integer"
You will have to retype this query using an explicit cast (#7)

Any ideas?

Fred Parkinson
Association of Bay Area Governments