I am not sure, what is the problem. When I install the mod_pagespeed on my Centos VPS, it make the Apache crushed. It ate a lot of memory, until over the memory limit. I have to restart the VPS.
Just a few minutes, it happened again.
So I have to remove it and use my manual optimize. Actually, Google mod_pagespeed does not make my web page faster. Same pagespeed score. Same YSlow score.