It’s been a while since I upgraded my ports tree, and I ran into errors when I upgraded the tree using portupgrade today. I found that making lang/ruby18 the default requires special handling of portupgrades. I handled the situation this way: ‘pkgdb -F’ to update the package database and ‘portupgrade -va -x openoffice’ to upgrade the ports which failed to upgrade earlier. Then I ran ‘pkgDB -F’, ‘portsclean -CDD:in `require’: No such file to load — pkgtools (LoadadError)”]
Source: https://taosecurity.blogspot.com/2004/03/portupgrade-errors-its-been-while.html