remove <prim-key-class> declaration from your ejb-jar.xml
I tried that method but then the problem was that the generated SQL gave errors.
But on the other side I found the problem.
my primary key getters and setters where still of type long and not of type java.lang.Long.
My question now is: how can you use primitive types as primary keys in CMP?
just declare the field as 'long' in your CMP implementation and mark it as your primary key field in ejb-jar.xml. Do not use primkey-class at all, it is only necessary for composite primary keys