From what I've heard from the support, the most frequent mistake in installing a software is putting it in a wrong folder, and then not finding it anymore.
To make sure that it's the right software you start, you could de-install 0.66 before installing 0.70.
The watermark is a restriction in the free version. If you buy Lite-c, or in the near future own A7 you can export to executable and the watermark will be gone.