Payment errors - orders doesnt appears

[AtthysKA]

Please help us, we have a serious problem in our shop.
While someones orders something and clicks on any kind of payments, the shop has an error.

We have 3 different payment method and both gives error:
If I choose bank transfer: 500 Server Error
PayPal: redirects to the Paypal site, can do the payment, but after that redirects back to an empty page. The payment made (i see in the paypal account), but the order doesnt appears in the backoffice.
COD: opens an empty page (validation.php).

Shop: tiendapescadeportiva.com

We just started to use multistore, so maybe some settings error.
I checked the bankwire modul file permissions: 755 (tried 644 also, nothing changed, so probably not this one)

Tried to clear the cache also, no result..

Please help! Thanks!

[tuk66]

Can you enable Debug mode to see the error, instead of the blank page?

[AtthysKA]

Thank you for your help!

I just enabled debugging.

 

I investigated what happened, and I think the issue can be connected to 2 newly installed modules:

1. Cash on delivery (COD) v1.0 - by maofree

2. Mega Customers v2.5 - by www.alabazweb.com (spanish special tax)

 

Probably the 1st causes some errors, as I reseted, and now the bank transfer is working ok. Will test the paypal payment, but the COD still has error, (see debug msg)

Can you help me how to fix this error?

[tuk66]

Can you share the errors?