that workaround seems to have fixed my buggy IPE. Meanwhile that goes against my wish to install only the IPE since the Packs seem only to be accessible from IDE....:/ But at least i can choose the device and programmers now within the IPE. Havn't tested the programming though but i'd guess that this should work now.
For information, i already had that problem in the past, and noticed it only happened every time i tried to install the IPE alone, without the IDE, for example on a laptop only used to program devices but not edit code.
I guess the IPE installation "only" misses installation points that are completed with the the IDE installation.