PCBSD 9.1 Beta 1 upgrade, upgrade jails not working
The freebsd-update service isn't going to work on jails created on the
snapshots / beta, and won't work until we hit 9.1-release. They only
patch the "official" releases, so in this case, 9.0, 9.1, 9.2, etc. Once
9.1-Release hits, you should be able to run freebsd-update to get
security patches, or "freebsd-update upgrade -r 9.1-Release" to upgrade.