Here is how to get the free HD Video Repair Utility Demo version running without any struggles, problems or limitations:
In the options of the Demo, paste the following into the "Custom repair parameters" box:
That's it! You just legally saved 99€!
The next file you will try to repair, will have the full length. Don't listen to the warnings saying it's only gonna save 50%, it'll save everything with the custom repair parameter set.
I made a screenshot so you guys can see how to do it.
PS: If the program REALLY helped you and you have enough money to afford it, pay for it and support development. The programmer(s?) had a hard time to get this excellent program working and should be rewarded for it.