It looks like you are trying to use the IIF statement to branch query results when it is only meant to provide an either or value for a single field.
Example: If the check-box is true, fieldA is this value. If the check-box is true, fieldA is another value.
You are trying to use it to put a where statement in a query based on the value of the chkConfigNote field. You would have to use an If-Else Statement for that.