Barcode scanning error

[coyote]

Hi,
I have an inventory system designed in access 2007 that tracks products
This thing was working well until i introduced barcode scanning.
The forms have the required fields.
When registering a product a barcode is entered in a barcode textfield and saved to the table.
When selling the product there a few choices to lookup the product.

1. Using the product code
2. using the product-id
3. using the barcode

The other two are working except barcode scanning where i get the error
Error 3341.
attached are pics of the system with error highlighted and the relationship window with only necessary relationships.
The database is huge to attach.

 

[Trevor G]

The images aren't clear are you using BarCode Fonts to identify the product?

 

[coyote]

i have come to realise the problem is not the barcode scanner.
After scanning the product i want the user to see all the other details like productcode(sku), price and all that. The only problem is that the barcode is not the primary key as some products sold don't have codes. so am using dlookup to find the productid as shown below.

Me.product_id = DLookup("product_id", "Products", "BarCode=" & "'" & Me.BarCode & "'")

This is when that error occurs
This is a main/subform scenario.
Main form has
SaleID,SaleDate,CustomerID
Subform has
SaleID(foreign key)
product-id(foreign Key)
Barcode
productcode(sku)
price
qty