Argument are of wrong type?

Hi there, I have error as image shows."{"Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another."}" please need your advice to work this out. appreciated.

// Return the records you need
rs = new ADODB.Recordset();
rs.let_ActiveConnection(cn);
rs.CursorLocation = ADODB.CursorLocationEnum.adUseServer;
rs.CursorType = ADODB.CursorTypeEnum.adOpenForwardOnly;
rs.LockType = ADODB.LockTypeEnum.adLockReadOnly;
rs.let_Source("SELECT Blockno, Number  FROM Table1 Where Date between " + "#" + S_Date + "#" + " and " + "#" + E_Date + "# ORDER BY Blockno");
rs.Open(null, null, (ADODB.CursorTypeEnum)(-1), (ADODB.LockTypeEnum)(-1), -1);