Admitedly the error itself says its not supported… but why? Doesn’t the container have to take care of this for you, not ME?
The way I managed to do this was have an AbstractActionForm class that extends ActionForm and I have 8 classes that extend the AbstractActionForm class. I went in (while tomcat was running in debug mode) and changed the AbstractActionForm (to implement Serializable for the container’s sake) and hit save, and this popped up.
Please feel free to close this, I just wanted to make you aware of it incase this is unusual for this to popup.