@alto55. Maybe I gave the wrong impression. The links should have showed you that it is not the code that is the problem, it is the setup on your PHP server. You have all the functions available and callable on your PHP server, but it seems that the mime database that those functions use it somehow not setup properly. This is something that your server administrator can help you with. Check this link on PHP.net.
You can easily run a simple test to see if your fileinfo functions are working correctly. You don’t need to be a savvy PHP programmer to do that. If you know the basics, it should be doable. I necessary, i can help you formulate a test script. However, have you checked your PHP error logs for any errors or warnings? If yo haven’t please do and let me know.