"pkg_delete -f" does not work right

[Todd Gruhn <tgruhn2%gmail.com@localhost>]

I built and installed ninvaders-0.1 .
When I delete, I get this:

gandalf# /usr/sbin/pkg_delete -f ninvaders-0.1.1nb1
/usr/sbin/pkg_delete -f ninvaders-0.1.1nb1
pkg_delete: Opening pkgdb failed

I followed the page
https://pkgsrc.org/pkgdb-change