visio internal error #3400 Action 1004 Save

[opportunities]

  I'd be eternally grateful if anyone could help me resolve this issue. If I tray to save any file with an embedded PDF i get the error:

Visio internal error: #3400
action: 1004 save
First try closing and reopening the file. Next try restarting Visio.

I've tried those actions, to no avail. It still refuses to save any files with PDFs. The obvious answer is "Don't use PDFs." Unfortunately, that's not an option, unless I want to fall even further behind than I am now.

Many Thanks