Hi Konrad,
Can you let us know the service patch for BO 4.0?
Check this SAP note:
1622652 - Error 'java.lang.NullPointerException: No business layer sent back from server' when importing a migrated Qaaws in Dashboard Design
Also check the right on the universe, sometime the issue can occur due to insufficient authorization.
Try to give rights to Universe.
Then give rights to Connections.
- Kuldeep