I re-installed libncurses5 version 5.7+20100313-2 from Debian unstable and the problem did not re-occur, so it appears that the shared library file on my hard disk had become corrupted.
Please close the bug and thanks for your time. Arthur. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org