Hi,
it depends on your system configuration. Those are settings of php, so the first place I would try is a php.ini file in the EPESI root directory. Then you can try in .htaccess or global php configuration.
Remember to restart http server after change in case of global php.ini modifications. Try to find proper solution on the web. There are plenty of questions like yours.
Well, as you can see, your green 64MB is not enough. So why it's green? Because we've tested that in most situations it's enough. You should increase that too. 128MB or even more if it's your server and you have spare resources. This is a memory that is used per one server request, but it's freed right after it's closed.
Regards,
Adam