eBay not recognizing upc codes

[re-past]

eBay’s program will not accept my UPC code when creating my listing. This has happened on two completely different products.  I enter the number as read at the booth of the bar code, and I keep getting a “NOT FOUND” message. Any help would be greatly appreciated. 

[disneyshopper]

What do you mean by "booth of the bar code"  ?

[re-past]

Sorry. Bottom of the bar code. So I enter that number in the field for upc code and eBay gives me a NOT FOUND message.