Automated tests do not run. Test cases go to state "In progress" and then shortly after to "Active"

What it almost sounds like is that the machine in question is not being launched in a state where the UI Desktop is available.  TestExecute/TestComplete knows that it can't really run without access to the UI.  So, if the machine is at the Windows lock screen or there is no actual console UI available, this could be the cause of your problem.  Just a guess, mind you.