Combo's And Queries

Quick question for you non-newbs out there...

I have two combo's on the same form, cboFName, cboLName. Trying to make some kind of a cascading combo thing, where when a cboLName is selected, my cboFName will be filled with All the firstname's that share that common last name. All of this data is on the same table, and here's my SQL for the queries at the moment:

SELECT DISTINCT tblContacts.LastName
FROM tblContacts
ORDER BY tblContacts.LastName;

SELECT tblContacts.LastName, tblContacts.FirstName
FROM tblContacts
WHERE (((tblContacts.LastName)=Forms!test!cboLName))
ORDER BY tblContacts.FirstName;

For some reason, the first query for my cboLName (although it works as a stand alone query) gives me a combo box full of blank names. Besides that, can anyone see anything wrong with my code?

Thanks,
Paul