"An error was encountered while retrieving page content"

This error message is usually an indication of a corrupt PDF file. The corruption could be in your base file, but also in the file from which you are trying to insert the page. There is nothing you can do to make this work - PDF files are in most cases impossible to repair. To find out which file is causing the problem, you could try to insert as page from a known good file. If that works, the problem is very likely in the file you want to insert from.