Rijndael.php openssl_decrypt padding with \0

[Arnout]

hi guys.

i have some problems in the backend. 

Wenn aktivating a module (in this case PayPal plus) i get a white screen.

Error report says:

Warning: openssl_decrypt(): IV passed is only 7 bytes long, cipher expects an IV of precisely 16 bytes, padding with \0 in /html/prestashop/classes/Rijndael.php on line 85
 

but how do i pad the IV ? and does that really do the trick?

Hope somebody can help, i really cannot find anything.

Thanks in advance

prestashop 1.6.1.19

php 5.6