VB6 SP6

I am try to convert a date string to date and insert it into a table (modDate Date). I am getting a data mis-match error but in debug, it appears that the data has been converted.

Code:
Dim ModDate1 As Date
ModDate1 = CDate(Format(flDrawings.ModDate, "MM/DD/YYYY"))

"VALUES ('" & IIf(IsNull(Name$), "a", RTrim(Name$)) & "','" & IIf(IsNull(Revision$), Null, RTrim(Revision$)) & "','" & IIf(IsNull(Descr$), Null, RTrim(Descr$)) & "'," & ModDate1 & ")"

Immediate Results
INSERT INTO engfiles(drwName,Rev,Descr,ModDt)VALUES ('WIDGETII','a','',7/12/2007)