VM error codes

[green-products.co.uk]

Hello,

Can anyone provide a list of VM errors and what causes them. I am not very technical so if you reply please keep that in mind.

I currently have an error Programming error,Paypal expresscheckout: virtuemart_paymentmethod_id is 0.

It is when I select the Paypal option - I've checked that it has a paymentid in VM so I dont understand what is going on.

Surely if Paypal is appearing on the screen, then VM is picking it up - so why does it not pick up the paymentID with it?

Joomla version 3.4.1 VM version 3.0.8

Thanks