Working with Oracle Reports Layout is always tricky and complex, as the error messages can be misleading/ difficult to debug. Few of the common error message that you get when working with report layout are
1. REP-1212: Object is not fully enclosed by its enclosing object 'Body
This error occurs usually if you increase the report width/size or number of columns in the report.
Main cause of this issue is the number of columns and rows in the report don't match with number of columns and rows in the Printer style.
Change the Style or make the number of Rows and Column in concurrent Program definition same as the Layout Character widht and size.
2. REP-1219 'margin' has no size -- length or width is zero
Again this error may occur when your playing with the frames in the report layout. When additional columns need to be added or layout needs to be modified, its required to modify the frames. In this process the widht of fields that are contained with in frame becomes less than one character wide and it results in the above error.
Identify the fields within the Frame for which error has been thrown which has size less then 1 character. And increase the size of field to more then one character.