QVP trial versions did not support being used as a preview handler in the past, while the full version worked well.
I think trial versions then did support being used as a preview handler, for at least a while, but maybe that has changed again. That seemed to be how things were the last time the Quick View Plus post was updated, unless the information was incorrect, but that was some time ago.
(I've just updated the post again to say that trial versions may not work, based on what you've said.)