В чому може бути причина цього попередження?

PHP info показує що локально функції відключені:

 

 

Dangerous PHP Functions Enabled

Some functions are enabled on your server which have the potential to cause serious damage to your community or server. If you are in a shared hosting environment, some of these functions may bypass the restrictions which prevent one account on the server affecting another. Their presence also increases the amount of damage that could be caused if your AdminCP is compromised.

Since Invision Community, and most other web applications do not use these functions, we recommend disabling them on your server, at least within the directory that your community is installed in. You should contact your hosting provider or system administrator and ask them to be added to the disable_functions PHP setting.

exec system passthru popen proc_open shell_exec

Зайди у каталог php-bin знайди php.ini 

disable_functions = exec, system, pcntl_exec, popen, proc_open, shell_exec прибираємо (PHP)
display_errors = Off (прибираємо показ помилок php)