editing a form letter after printing to file

This problem has come up before, but is closed as the original poster did not reply to a suggested solution, (which didn’t work).

Using Version: Build ID: 410m0(Build:2)
Operating system:
Kubuntu 12.04 LTS, using the repository http://ppa.launchpad.net/libreoffice/ppa/ubuntu precise main

I’m using the form letter to print address labels: I set up the form fields, attached the data source and the correct table then went to print > print form letter > print to file.

So far fine. But when I opened this file (to see if I had made any mistakes, or if any addresses didn’t fit on a label and needed manually adjusting), I had the following error when attempting to edit:

Readonly content cannot be changed.
No modifications will be accepted

The document itself is not read-only - the permissions were set to user (me) read and write, and I can add extra pages at the end then save - it’s just the content of the labels which I can’t change. Similar files made with previous versions of LibreOffice do not have this problem.

Please could someone let me know how to ‘unprotect’ or un-read-only this section?
Many thanks for your help!

I have a similar problem with a single page document (.doc) originally written using MS Word. My current version of LO id (Windows 7 Pro) but this has been an on going problem I’ve had with the same docoment for 3-4 years. It is a membership document so every year the dates in it need changing. The only solution I’ve found so far is to edit it with MS Word which seems a bit drastic but I have been unable to find a way in LO to uprotect a table cell to allow editing of the document.