gnucash can't find tutorial & concepts guide

[morris beavers]

 New user/installation on RaspberryPi.

When I select Help/Tutorial and Concepts Guide, I get the message:
"GnuCash could not find the files for the help documentation. This is
likely because the 'gnucash-docs' package is not installed."

dpkg --list | grep gnucash reports:
ii gnucash 1:2.6.4-3 armhf personal and small-business financial-accounting
software
ii gnucash-common 1:2.6.4-3 all common files for the financial-accounting
software Gnucash
ii gnucash-docs 2.6.4-1 all Documentation for gnucash, a personal finance
tracking program

How to fix the help menu?

Thanks, Morris