[TYPO3-commerce] MAIN:FATAL! Error

[Peter]

Hi All

I am having a problem with the commerce and paypal extensions
I only have paypal as a method of payment and I have disabled/hidden
credit card etc.
The shop is ok and I can choose items and put them in the basket
but when I put an item in the basket and click on go to check out.
I get the following error

MAIN:FATAL! No payment possible because I don't know how to handle it! 
(class not set!:, file not found!:)

In `tx_commerce_articles` table
I have a row for paypal it has a uid of 14 and a pid of 104
the classname is set to Paypal.

Under the templates Constants: under PLUGIN.COMMERCE: General
What would be the Payment Article?
ie
Payment Article = [plugin.tx_commerce_lib.paymentArticleId]
The ID of the default Payment Article

I have tried both 14 and 104 as default values but it does not make any 
difference
I have also tried setting plugin.tx_commerce_lib.paymentArticleId in the 
template file
directly

If I enable any other method of payment I do not get this error.
What do I need to do to make this work?

Peter