Printing Web Dynpro ABAP Applications l_appl->print_page( )

Hello

I have followed the implementation guide in SAP Help ( link below) and checked my implementation multiple times.

Link: http://help.sap.com/saphelp_nw70ehp2/helpdata/de/f8/872806981d4411b5ce51a00207ed31/content.htm

So I have also checked, that the name of the event handler in method lo_api_controller->get_action has the same name as the Button event handler in the view.

I have registeed the event in the method WDDOINIT of the view.

However I get an error as displayed bellow.

Please can anyone help me to find out how to bring it to work correctly.

Many thanks

Christian