Hi Ian
The only other thing I can suggest you try is to open a new document and then try and insert the file you are unable to open.
Failing that I have run out of ideas.
If you are happy to provide one of the file I can see what I can do and let you have it back. If you dont want to put it on here you can send it to OTPM@blueyonder.co.uk.
Tony (OTPM)