I just checked this issue against 5.0.3.Final and the exception is as follows:
org.hibernate.MappingException: An association from the table QUUX refers to an unmapped class: com.bar.Foo
where QUUX }}is the table name and {{com.bar.FOO is the unmapped entity.
There's still no word about the referenced entity name, but I guess the information given is still sufficient to solve issues like the one described above.