Okey. Finally some progress. I have now setup successfully my PC based on the already working laptop. I use Android Studio (latest x64), and JDK 8 (thank you Yves for your tip above). Still got the build.xml error on my PC until I thought of just renaming C:\Program Files (x86)\Clickteam Fusion Developer 2.5\ and copying the complete Clickteam installed folder from my laptop. Now my PC works (Build 29 selected).
I ran a file / folder compare with hash differences, and these two Clickteam versions are different here and there. I want to investigate further until I can send some logs here though. Want to make sure both are updated etc etc (which I think they are but still). The build.xml error was solved without manually adding the tools\ant\build.xml++.