I have the same problem and receive the same error message in the console.
When I open Pages/Numbers/KeyNote/TextEdit from a file created in my Sandboxed App
1) I receive this error
2)I can not directly save the opened file with these applications because it's blocked: it asks to duplicate the file into a different location inside the user home directory. This is quite annoyning because I need to keep the file in that directory in order to receive File System events.
Do you already solve this problem?