Was setting up a desktop as testbed for playing around with betas and new versions of software. Set up another WAMP install with Apache 2.4.8, MySQL 5.7.11, and PHP 5.6.19 and 7.0.4. Installed kiwitrees version 3.2.1 without any issues. Logging out, it did not go to the default page but some of the header and the footer was there. Reopening the page gave the same situation.
The top of the attachment is the screen what both the one log off and the opening screen looks like. The bottom of the attachment is the resulting PHP error log.