Go into General Settings and disable the JS/CSS speedup tools. Then clear your template cache by running cleanup.php or do so from within tools > maintenance.
The JS/CSS speedup tools are enabled by default on install - trouble is they don't work 100% under all server environments.
https://bugtracker.qtmsoft.com/view.php?id=38985
It's a shame, because without that functionality, X-Cart is loading dozens of JS/CSS files, which only slows down your store.
Hopefully this will be totally fixed in v4.4.3