Just want to inform everyone about the following problem. It may happen when checking out OpenEMS under Windows:
Recommendation to all developers:
Please take care about the size of bundle and package/class names. There is not much room left for larger filenames.
Solution for this error:
Reduce the length of the local directory structure to something smaller than 50 characters (my local checkout path has ~60 characters (D:\50_Projects.…\openems)) and checkout OpenEMS again.