i just finished the course this week and also run into this error. i did the followings then the issue is gone.
in the SAP HANA cloud platform cockpit, i did the following steps.
1) unbind the application from the schema and then delete the schema. refer to the picture for details.
In the eclipse, i did the following steps.
1) Delete this hello world project.
2) Reimport this project from the sample folder and make sure the sample is copied to the
workspace.
Hope this help.
regards,
Yueqiang