After enable the latest version (including all submodules) at once got this:

Fatal error: Only variables can be passed by reference in /home/MYSITE/public_html/sites/all/modules/advagg/advagg.module on line 500

Comments

Component:Code» JS CDN

Seems like the issue appear if you have jQuery Update installed (even if the CDN options are not enabled). I manually installed ACJA and reinstalled it via Drupal module installer, all went right, went to admin/reports/status and it reported the problems with jQuery Update as warnings, then i went to jU admin and enabled CDN there getting the Fatal Error again.

What theme are you using? Line 500 is assuming you have a page_top defined. Also go to admin/config/development/advagg/info and under "Hook Theme Info", what is listed there? The code that is causing the fatal error is copied directly from core $variables['page_top'] = drupal_render($variables['page']['page_top']); template_process_html().

I tried to repo the reported bug and I couldn't get any errors.

Status:Active» Postponed (maintainer needs more info)

I did a search of all themes and modules #1946218: test with other modules & themes & didn't find a smoking gun that would cause this. I need more feedback in order to repo the bug. Marking as postponed until I get feedback.

Status:Postponed (maintainer needs more info)» Closed (cannot reproduce)

Closing this issue as I can't repo it.