The multi-part identifier Error

Hi Everyone.

Currently I encounter error while. executing my custom button name “Create TP Number”.

and here my sample code.

public static void CreateTPNumber(PMQuoteMaint pMQuoteMaint)
{
    using (var ts = new PXTransactionScope())
    {
        PXResultset<CROpportunityProducts> pXResultsetCROpportunityProducts = pMQuoteMaint.Products.Select();

        PXResultset<PMQuoteTask> pXResultsetPMQuoteTask = pMQuoteMaint.Tasks.Select();

        List<CROpportunityProducts> cROpportunityProductsDuplicate = pXResultsetCROpportunityProducts
            .RowCast<CROpportunityProducts>()
            .GroupBy(x => new { x.InventoryID, x.TaskCD }).Where(g => g.Count() > 1)
            .SelectMany(g => g)
            .ToList();

        if (cROpportunityProductsDuplicate.Count() > 0)
        {
            foreach (CROpportunityProducts pMQuoteTask in cROpportunityProductsDuplicate)
            {

                InventoryItem pXResultInventoryItem = SelectFrom<InventoryItem>.Where<InventoryItem.inventoryID
                    .IsEqual<@P.AsInt>>.View.Select(pMQuoteMaint, pMQuoteTask.InventoryID).FirstOrDefault();

                throw new PXException(Messages.TravelPackageErrorMessageDuplicate(pXResultInventoryItem.InventoryCD));
            }
        }

        if (pXResultsetCROpportunityProducts.Count <= 0 && pXResultsetPMQuoteTask.Count <= 0) return;

        foreach (CROpportunityProducts cROpportunityProduct in pXResultsetCROpportunityProducts)
        {
            CROpportunityProductsExtension cROpportunityProductsExtensions =
            PXCache<CROpportunityProducts>.GetExtension<CROpportunityProductsExtension>(cROpportunityProduct);

            if (cROpportunityProductsExtensions == null) return;

            string status = cROpportunityProductsExtensions.UsrStatus ?? String.Empty;

            if (status == Messages.openStatus
                && cROpportunityProduct.TaskCD == null)
            {
                InventoryItem inventoryItem = SelectFrom<InventoryItem>.Where<InventoryItem.inventoryID
                    .IsEqual<@P.AsInt>>.View.Select(pMQuoteMaint, cROpportunityProduct.InventoryID).FirstOrDefault();

                if (inventoryItem == null) return;

                for (int i = 0; i < cROpportunityProduct.Qty; i++)
                {
                    PMQuoteTask pMQuoteTaskNew = new PMQuoteTask();

                    pMQuoteTaskNew.Description = inventoryItem.InventoryCD;

                    pMQuoteMaint.Tasks.Update(pMQuoteTaskNew);

                    pMQuoteMaint.Actions.PressSave();
                }

                pMQuoteMaint.Products.Delete(cROpportunityProduct);

                foreach (PMQuoteTask pMQuoteTask in pMQuoteMaint.Tasks.Select().RowCast<PMQuoteTask>()
                    .Where(x => x.Description == inventoryItem.InventoryCD))
                {
                    bool isTaskCD = pXResultsetCROpportunityProducts
                        .RowCast<CROpportunityProducts>().Where(x => x.TaskCD == pMQuoteTask.TaskCD).Any();

                    if (!isTaskCD)
                    {
                        CROpportunityProducts cROpportunityProductsNew = new CROpportunityProducts();

                        CROpportunityProductsExtension cROpportunityProductsExtension = PXCache<CROpportunityProducts>
                            .GetExtension<CROpportunityProductsExtension>(cROpportunityProduct);

                        CROpportunityProductsExtension cROpportunityProductsExtensionNew = PXCache<CROpportunityProducts>
                            .GetExtension<CROpportunityProductsExtension>(cROpportunityProductsNew);

                        cROpportunityProductsNew.InventoryID = inventoryItem.InventoryID;

                        cROpportunityProductsNew.Qty = 1;

                        cROpportunityProductsExtensionNew.UsrSuggestedMinimumBid = cROpportunityProductsExtension.UsrSuggestedMinimumBid;

                        cROpportunityProductsNew.TaskCD = pMQuoteTask.TaskCD;

                        pMQuoteMaint.Products.Update(cROpportunityProductsNew);
                    }
                }
            }
        }

        pMQuoteMaint.Actions.PressSave();

        ts.Complete();
    }
}

I hope you can help me. Thanks.