Well, I tried to do the change mille71 suggested, and it worked!
It’s my first time using the plugin, it wasn’t installed before. The error message:
Parse error: syntax error, unexpected ‘$pdf’ (T_VARIABLE), expecting identifier (T_STRING) in C:\sites\local\wp-content\plugins\quiz-master-next\includes\mlw_quiz.php on line 687
And I think this will help you track down the problem: just tried the same website, but in an environment with PHP 5.3. The plugin worked.
I just tried version 1.9.5 and had the same problem as GHGadmin. I’m running WordPress 3.7 and PHP 5.4.