Upgrade from 11.1 to 11.2 failed

I have a problem with upgrading my FreeBSD.
When I typing: freebsd-update -r 11.2-RELEASE upgrade
I receive:
src component not installed, skipped
/usr/sbin/freebsd-update: config_freebsd-update: Permission denied
Error processing configuration file, line 78:
==> freebsd-update fetch

Any ideas, how to solve this problem?
Are you doing this as root? Also check for errors in /etc/freebsd-update.conf, the default file only has 76 lines so there could never be an error on line 78.