Moodle Themes and cPanel have never played nicely together for as long as I can remember.
There may be a (read/write/execute) permissions problem with the files for the More theme LESS processor. You could check that, or get your Hosting company to do that for you.
It might be that the version of PHP is actually wrong for the version they have uploaded?
One other reason that the More theme is not working, and no one has questioned it yet, is that if you have added any CSS ( LESS or normal CSS ) to more/less/moodle.less, then it could be that you have made a mistake in the LESS/CSS mark-up and that is enough to break the theme! I know I do it all the time...
Cheers
Mary