Hey Mauricio,
Sorry for the bad question.
Okay.
I get the same error like above:
]while storing workItem 1: de.toni.analysis.MyDataCalculation
In my Javafile MyDataCalculation I can implement the Serializable interface and the error dispear for this Class.
But I have got much more Classes in Libaries (from work), where I haven´t got the *.java file, only the class files. There I can´t implement the Serializable interface. :(