Hi all

I've got an external data query set up and I'm trying to parameterise it. I've done exactly the same thing with various other queries in the workbook, but there's something about this one that Excel doesn't like:
PHP Code: 
SELECT 
    supkey, 
    SUPCompanyName, 
    LSMIdNumber, 
    MATKey, 
    MATDescription,
    MATRefiningChargeGBP,
    LSMDiscountPercent,
    LSMSuppressEaLevy,
    LSMSuppressTransportCharge,
   ISNULL((SELECT SUM(JIMQuantityActual)
       FROM   dbo.tb_JIMJobItem WITH (NOLOCK)
              INNER JOIN
              dbo.tb_JOBJob WITH (NOLOCK)
              ON tb_JIMJobItem.JIMJobId = JOBIDNumber
              INNER JOIN
              dbo.tb_MATMaterial WITH (NOLOCK)
              ON dbo.tb_JIMJobItem.JIMMaterialId = dbo.tb_MATMaterial.MATKey
       WHERE  JIMMaterialId = lsmmaterialid
              AND JOBArrangement in (select distinct supArr.arridnumber 
                                            from tb_ARRArrangement supArr (nolock) 
                                            inner join tb_SUPSupplier (nolock) on supArr.arrschemeid = supkey 
                                            inner join tb_ARRArrangement (nolock) sh on sh.ARRSupplierId = SUPKey 
                                            where SUPIsSchemeCode = schemeH.SUPIsSchemeCode)
              AND JOBCollectionDate >= '2012-08-01'), 0) AS ActualQuantityCollected, 
   ISNULL((SELECT SUM(CONVERT (DECIMAL(16,4), JIMQuantityActual) * CONVERT (DECIMAL(16,4), MATNetMarginFactor))
           FROM   dbo.tb_JIMJobItem WITH (NOLOCK)
                  INNER JOIN
                  dbo.tb_JOBJob WITH (NOLOCK)
                  ON tb_JIMJobItem.JIMJobId = JOBIDNumber
                  INNER JOIN
                  dbo.tb_MATMaterial WITH (NOLOCK)
                  ON dbo.tb_JIMJobItem.JIMMaterialId = dbo.tb_MATMaterial.MATKey
       WHERE  JIMMaterialId = lsmmaterialid
              AND JOBArrangement in (select distinct supArr.arridnumber 
                                            from tb_ARRArrangement supArr (nolock) 
                                            inner join tb_SUPSupplier (nolock) on supArr.arrschemeid = supkey 
                                            inner join tb_ARRArrangement sh on sh.ARRSupplierId = SUPKey 
                                            where SUPIsSchemeCode = schemeH.SUPIsSchemeCode)
                                            
              AND JOBCollectionDate >= '2012-08-01'), 0) AS TotalNominalWeightKg
FROM
    tb_SUPSupplier schemeH (nolock)
        inner join tb_LSMLinkSupplierMaterial (nolock) on LSMSupplierId = SUPKey
        inner join tb_MATMaterial (nolock) on LSMMaterialId = MATKey
Where 
    schemeH.SUPIsSchemeCode = ? 
SUPIsSchemeCode is a string, but when I try to use a cell value as the parameter, I get a Bad Parameter Type error message. I think Excel is expecting the value to be a date since if I try to enter a date, the query fires but I get OBDC errors.

Can anyone cast any light on this?