Hi Frank,
thanks for getting in touch and sorry for the trouble. I have never seen these specific error messages and could not find immediate help in a quick google search. Usually those initial build errors can be solved by following the steps listed here - but I doubt it will help in this case.
If you just want to have a first look at what you can expect from OpenEMS Edge + Backend + UI, we just added support for Gitpod, which builds an entire demo of all components in your browser and lets you play with it. For now you can use this link to try the ‘develop’ branch:
https://gitpod.io/#https://github.com/OpenEMS/openems/tree/develop
(Support for Gitpod with master branch is going to come with the latest release later today.)
Regards,
Stefan