21 Definition files referenced by Catalog Types were not found.
User tried creating a new WorkSet without selecting a valid template linked to an AECOsim dataset. That results in the creation of a Microstation WorkSet not an AECOsim WorkSet, and this WorkSet does not have the configuration variables with files required for AECOsim.
Create a new WorkSet with selecting an appropriate AECOsim template. Check Create a new Workset.