Unable to run MServer/module-info.java not found

I've followed the instructions to run it on Linux. While on raspberry ./gradlew start worked fine, on ubuntu I get "Project : => no module-info.java found". I have no idea what is the difference, both systems running "openjdk 17.0.11 2024-04-16"

Is there some precondition I've missed?

Remark: On Raspi it runs into out of memory exception, therefore I'd run it on Ubuntu