On my new servers Softaculous (userend part) wont run as its suposed to, because the variables isnt populated.
The problem is that in some cases, scripts, running /usr/local/cpanel/base/frontend/x3 (softaculous symlink is located in here), wont use CPanels PHP, but servers main PHP CLI instead.
The solution is to ensure, that server utilizes the cPanel PHP install instead of the main system PHP for scripts loaded via cPanel.
The process to make this change is as follows:
Only if the server output is:
stat: cannot stat `/var/cpanel/usecpphp': No such file or directory
Hopefully You find this solution usefull ;)