I've got exactly the same symptoms you describe. I'm running branches/1.3 on Postgres. In my a2billing_epayment.log for each transaction I get:
Code:
[checkout_process.php line:8-transactionID=72 ----EPAYMENT TRANSACTION START (ID)----]
[checkout_process.php line:9-transactionKey=ca54XXXXXXXXXXXXXXXXXXXXXXXXXX13 ----EPAYMENT TRANSACTION KEY----]
[checkout_process.php line:50- QUERY = UPDATE cc_epayment_log SET status = 2 WHERE id = 72]
[checkout_process.php line:61- transactionID=72 EPAYMENT RESPONSE: TRANSACTIONID = 72 FROM moneybookers; FOR CUSTOMER ID 290; OF AMOUNT 5]
[checkout_process.php line:127-MoneyBookers Transaction Verification Status: Failed | md5sig =E14xxxxxxxxxxxxxxxxxxxxxxxxxxx18
Reproduced Signature = E16xxxxxxxxxxxxxxxxxxxxxxxxxxx56 Generated String = 41xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx5GBP-1]
[checkout_process.php line:173-EMAIL SENT: SENT A WARNING EMAIL TO ADMINISTRATOR FOR EPAYMENT VERIFICATION FAILURE]
I think the moneybookers secret needs to be 10 characters or less and all in lower case, but I've still not seen it work myself.