DTS error when a parameter is added to an Execute SQL Task

I have an Execute SQL Task that is (hopefully) going to receive a global variable called startDate, which is set to a Date type. A shortened version of the code looks like this: DECLARE @startDate DATETIME, @endDate DATETIME SET @startDate = ? SET @endDate = DATEADD(DAY, 6, @startDate) INSERT INTO destinationTable SELECT * FROM sourceTable WHERE startDate = @startDate AND endDate = @endDate When I replace the parameter with a date (e.g. '08-01-2012'), the statement parses correctly; however, as soon as the parameter is added back in, the statement errs. I use DTS *very* rarely, so I'm basing this code entirely on Microsoft's Using Parameterized Queries . Can anyone enlighten me on how to correctly use a parameter in this situation? ---------- **Edit**: The error detail reads "Syntax error or access violation" which, considering the circumstances, I assume to read as a syntax error due to the addition of the "?".