Koen, i have run into an error with the new release 5e. The problem occured after i had made a string of changes for the scrin and had tweaked the settings in special powers and upgrades. I then went on to try to edit the Weapons Template, and an error message displayed.
Error type: EpyAttributeError
Error message: exceptions. AttributeError: 'NoneType' object has no attribute 'makeelement'
Since this error message first appeared, no matter what i try, including starting with a new project - whenever i select a weapon from the weapon template, this message now occurs.
Hope this information can be useful to you.
Lachlan