I know this has been discussed...

This is the problem im having

1054 Unknown column 'zen_order_id' in 'where clause'
in:
[select * from zen_paypal where zen_order_id = 5 AND parent_txn_id = '' ]
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Zen Cart 1.3.8a
Patch: 1::
Database Patch Level: 1.3.8

PayPal Website Payments Pro (v1.3.8a)

PayPal Express Checkout (v0.1b)

PayPal IPN (Basic PayPal service)