[AccessD] Query based on multiselect listbox

Dear Group

I am trying to use a multselect listbox to serve as a the parameter for a
query.  I'm using the IN operator but it doesn't seem to be working.  I'm
using A97.  Here is the SQL

SELECT Invoice.RDC
FROM Invoice
WHERE (((Invoice.RDC) In ([Forms]![frmWrkShts]![RDCCriteria]))
AND ((Invoice.[Invoice Date])<=[Forms]![frmWrkShts]![date]));

In the frmWrkShts, I have a text box (RDCCriteria) that is storing the items
selected from the listbox.  That part is working fine.  However, when I run
the query, 0 records are returned.  If I run the query with the items from
the text box, I get the correct number of records.  Is it not possible to
use the IN operator with a parameter query?

Tim Thiessen