SAP Message 37019 - Flow logic in screen & & is empty

Diagnosis
When the system checked the screen it found out that the flow logic isempty (the flow logic does not contain any valid lines).

System Response
The system considers the screen to be destroyed.
The flow logic of every screen must contain at least the statements
PROCESS BEFORE OUTPUT.
and
PROCESS AFTER INPUT.
The system stops processing the screen.

Procedure
Contact your system administrator.