SAP Message CACSGEN257 - Not able to activate class/interface &1

Diagnosis
The activation of a class failed.
If you receive this message, a functioning template object exists andthe generated object indicates an error. A possible reason for thiserror could be that required objects (such as tables) were notgenerated.

Procedure
Use the syntax check for the generated class to receive moreinformation.
In most cases, the problem can be resolved by generating the wholeapplication again.