Hello porthos,
Boy, this one is not an easy one to troubleshoot.
So the changes are now in the php.ini file? Or are they still being set in .htaccess? I ask because we really only support changes to .htaccess as we have them listed in the user guide for removing index.php. Aside from that, we are just not able to guarantee that other rewrite rules and such are not going to interfere with ExpressionEngine.
Aside from this being a memory issue I cannot think of what else it could be. It sounds like some pdf file take longer or more memory to upload than others so we get a failure which seems random to us.
We can try to update ExpressionEngine, but I am not sure that the issues lies with the version.
Is there anyway for you to get shell access to your web server? Can we look at the logs first hand? Not that I do not trust your provider, but it would be good to see of there are errors and even if there is not, it would be nice to know if the server things the uploads are find, even that would give us more direction.
Let me know your thoughts,
For Reference:
memory_limit
This sets the maximum amount of memory in bytes that a script is allowed to allocate.
Default size 5.3 in is “8M”
post_max_size (must be greater than upload_max_filesize)
Sets max size of post data allowed. This setting also affects file upload.
Default size in 5.3 is “128M”
upload_max_filesize
The maximum size of an uploaded file.
max_execution_time
This sets the maximum time in seconds a script is allowed to run before it is terminated by the parser.
Default setting in 5.3 is “30”