With regard to the issue, it may not be possible to recover the flipchart however a suggestion would be to have a look at the MAC temporary folders to see if the flipchart may be stored there.
To find this on a MAC, Ggo on terminal and type echo $TMPDIR or open $TMPDIR (to open Finder on that path). There you will find temp files stored by the Applications running. /tmp is the general location for temporary files in Mac OS X.
Hopefully the flipchart will be located here and be recognised as an ActivInspire file.
Promethean Technical Support