Bom error:price list does not exist;specify another pricelist

Dear experts ,

I am running an addon(vb) that creates bom.The problem is that when in the lines of bom the products have different pricelist i faced the error " price list does not exist;specify another pricelist [ITT1.PriceList] "

The code for this field :

       If rsMaterial.Fields.Item("IssueMethod").Value.ToString = "M" Then

                        vProdTree.Items.IssueMethod = "1"

                    Else

                        vProdTree.Items.IssueMethod = "0"

                    End If

When i am running the code the values are correct and when the code add the bom i have this error.

Note that the value 'M' comes from a table in sql.

Best Regards