Date Conversion

Code:

DIM mySQL
Dim start_week_1
Dim end_week_1
Dim date_param

date_param = "09/28/2006"

start_week_1 = date_param-(datepart("d", date_param)-1)
end_week_1 = start_week_1 + 6

I keep receiving the following error:

Microsoft VBScript runtime error '800a000d'

Type mismatch: '[string: "09/28/2006"]'

/Overtime/SQL.asp, line 43

I know that there is a conversion necessary. Possibly Cast(date_param as varchar),but that does not seem to work.