Queries :: Multi-parameter Select Query

I created a form that has 3 multiple drop-down selections that is supposed to select records from [TableName_1] based on those selections. I initially created the query using the query designer with actual "hard coded" selections to make sure it worked. When it gave me the expected records, I changed the criteria from the "hard coded" option to the input form's control reference [Forms]![FormName]![ComboName]. I did this one at a time and tested after each change.

After the first change, I got exactly what I expected.

After the second change, it seemed okay. (note: I put the criteria on the first criteria line in the query designer, not on the second line)

After the third change, I get the dreaded: The expression is typed incorrectly or is too complex to be evaluated....

Here is the SQL:

SELECT M_Lending_Institution.InstitutionName, M_Lending_Institution.GeoRegionID, M_Lending_Institution.SpecialtyID, M_Lending_Institution.SBA
FROM (SELECT M_Lending_Institution.InstitutionName, M_Lending_Institution.GeoRegionID, M_Lending_Institution.SpecialtyID, M_Lending_Institution.SBA FROM M_Lending_Institution) AS LenderSearchQuery
WHERE (((LenderSearchQuery.GeoRegionID.Value)=[Forms]![LoanSearch]![CmbPrefGeo]) AND ((LenderSearchQuery.SpecialtyID)=[Forms]![LoanSearch]![CmbSpecialtyArea]) AND ((LenderSearchQuery.SBA)=[Forms]![LoanSearch]![CmbSBA]));

And once this is sorted out, yes I want to be able to allow for all records to be returned if any of those fields is NULL. I've read a LOT of posts around this subject, but I can't seem to find anything that answers my question without jumping into advanced VBA code.