Just did a fresh install of Timetracker on to a Ubuntu 16.04 LTS server. Server is running Apache 2, MariaDB, and PHP7. I've configured the Timetracker according to the linux install docs, and have created the database from the dbinstall.php script from within the browser, and confirmed that all tables were created correctly using phpMyAdmin. I've created a user, and have entered some time values (durations) for this week.
When I try to run a report of the "this week" time period, with Project, Duration, and Note fields selected, and hit Generate, I get an error stating that there is an incorrect "Start date" data and incorrect "End date" data. Both the start date and end date fields are left blank. If I instead fill in the start and end date fields by using the calendar buttons next to them, and don't use the select time period drop down, I still get the same error.
Timetracker version is listed as Anuko Time Tracker 126.96.36.19982 on the footer of the site.