The fix to this problem is to update the server to run php version 5.6 or higher to process .php files.
I too have the 500 server problem. When I upload the woocommerce plugin while the enfold theme is active I get the 500 error. So I turned the woocommerce plugin off uninstalled the enfold theme and reloaded the woocommerce plugin which installed fine. Then I reloaded the enfold theme and as soon as I activated I get the 500 error. How to fix this problem?