This error can occur during the Hibernate-reverse-engineering step and the causes of the problem can be anything from DB permissions to JDBC driver bugs or unimplemented features.
When this error occurs, the first thing to do is check your log file located at: <workspace dir>\.metadata\.log
and look near the bottom of the file to see the exception message that has occurred. Sometimes the error will be very explicit like "Insufficient permissions" or "Method not implemented in JDBC driver". In these cases trouble shooting the issue and working around it can proceed much more quickly.
In most of the cases reported by users this issue is caused by an incomplete or buggy JDBC driver. For Oracle folks
the issue is almost always caused by using the old classes12.zip
driver and not the newer Oracle JDBC driver. This issue and the solution is discussed in this FAQ entry
We have also seen folks using a DB account with insufficient permissions getting this error, and as mentioned above, you can determine if this is the problem by checking the log file.