Cause
This error occurs if the schema file attempts to change a class from real to abstract and the change is not valid. This can be for one of the following reasons.
The class has persistent instances existing.
The class is a collection class and there are existing exclusive properties referring to this collection type. Exclusive references are always created when the parent object is created, so they must have a real (that is, non-abstract) type.
Action
Refer to your JADE messages (jommsg.log) log file for more details about this error.
Remove any persistent instances before changing the class to abstract.
For collection classes referenced by exclusive properties, change the type of the collection to real. Alternatively, make the reference to the abstract collection a shared reference rather than an exclusive reference.