Problem with 64bit ODBC driver between RHEL 6 and AS400 iseries database

Issue

• I am currently facing problems when configuring an apache server for the migration to RHEL 6.2, with an odbc link to an IBM As400 server.

I am using the pilot odbc iseries access7.1 64 bits provided by IBM, unixODBC 2.3.1 and php 5.4 with unixODBC support.
The link seems functional, I manage to connect to the base via the command isql and to execute SQL requests.
Nonetheless, it is impossible to read the results of a request via a php script. I get this error: 

• I receive the following error on RHEL 6.2 with odbc to IBM As400 server:

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 493921239296 bytes) in /home/www/imypdo/imypdo.php on line 122