I have had some very strange installation issues and found out that they are related to a wrong system time. The system time is necessary for encrypted connections (TLS/SSL) and if the system time drifts to much away from the current time the connection for downloading/installing fails and you get a half configured package.
Maybe it is worth to try
htpdate -t -s www.isc.org
before installing. This should set the system clock by a timestamp from a webserver.
ntpdate may also help, but NTP is sometimes forbidden in some networks.