what is the purpose of “Protect and EndProtect”?.

You can specify either in the style or in the layout set that a particular paragraph should not be slit in two by a page beak. If the page protect attribute is set then the complete paragraph is always output ona single page. This property applies only to that particular paragraph.

SAPScript provides the PROTECT… ENDPROTECT command pair to allow you to define the areas to be protected against a page beak on an individual basis. Thus the PROTECT/ENDPROTECT commands may be regarded as a kind of conditional NEW-PAGE command, the condition being whether or not the lines enclosed between the two commands fit in the space remaining in the current main window.