Do you run php as apache module or via fcgi? >>> apache module
You php is 64 bit? >>> 64-bit version of PHP
Did you try with php 5.6 or 7.0? PHP 7.1 is pretty new and I’m not sure if it has been fully tested with NC 11 (NC 12 will have full PHP 7.1 support). >>> Have tried both 5.6 and 7.0 with same results. will wait for NC12 to come out
Did you try setting this variable in php.ini? apc.enable_cli=1
Regarding the distributed cache error, did you install and configure Redis, and/or did you enable ‘memcache.distributed’ in your config file? You probably don’t need the distributed cache unless you have a large Nextcloud setup.
Can you just comment out the memcache-stuff from your config and run it without it for a moment? Does the upload work then? These could be two different problems.
If you have errors that say a module is already loaded, that can indicate that you haven’t configured everything properly and perhaps including more configuration files than initially wanted which could lead to settings that don’t work. Even though these errors are not related to your problem, this could perhaps help you to find it.
Other idea: Start Apache in debug mode and upload a file. Problem is that you get a lot of output and it’s not easy to spot the issue.