Random memory errors

Hi all,

I am currently pulling my hair out on a problem with one of my websites. I build a site voor https://www.stichtingvtv.nl which used to run perfectly. But a while ago fatal memory errors started appearing. The broke certain functionality(mostly in the admin section when i try to access the page overview).

I have tried just about every tip and suggestion i could find without any luck. I have tried:

1. to upgrade the memory limit in just about every possible location(.htacces, wp-config, php.ine, contacted my webhost). None of it works. The strange thing is that the memory limit has not even been reached. It is set at 64m and an example of the error im getting is:

   Fatal error: Out of memory (allocated 28049408) (tried to allocate 71 bytes) in /home/dosert/public_html/vtvtest/wp-includes/wp-db.php on line 1383

   The file and ammount of memory is not always the same.

2. Turn off all plugins and activate them one by one. (Tried deactivating and tried renaming the plugin folder). This does remove the problem, however it doesn’t matter which plugins i activate/deactivate. Any combination of plugins can break the site.
3. I have contacted my host to check if the hosting settings are ok. I’m running PHP Version 5.3.8. on an apache server. The memory limit is 64m according to the hoster(and checked it with a info.php file.)

I really don’t know what to do anymore. Any help would be greatly appreciated, since the website is already live and i want to resolve this for my client.