Zenoss 4.2.5: Graphing Stopped / Image Contains Errors

The image cannot be displayed because it contains errors.
zenrrdcached not running.

SSH to the Zenoss appliance.

[root@localhost]# service zenoss status
Daemon: zeneventserver program running; pid=4058
Daemon: zopectl program running; pid=4164
Daemon: zenrrdcached not running
Daemon: zenhub program running; pid=4211
Daemon: zenjobs program running; pid=4278
Daemon: zeneventd program running; pid=4344
Daemon: zenping program running; pid=4410
Daemon: zensyslog program running; pid=4530
Daemon: zenstatus program running; pid=4513
Daemon: zenactiond program running; pid=4552
Daemon: zentrap program running; pid=4629
Daemon: zenmodeler program running; pid=4634
Daemon: zenperfsnmp program running; pid=4666
Daemon: zencommand program running; pid=4696
Daemon: zenprocess program running; pid=4728
Daemon: zredis program running; pid=4732
Daemon: zenpython program running; pid=4767
Daemon: zenjmx program running; pid=4800

[root@localhost]# service zenoss start
Daemon: zeneventserver is already running
Daemon: zopectl daemon process already running; pid=4164
Daemon: zenrrdcached starting...
rrdcached: can't create pid file '/opt/zenoss/var/rrdcached.pid' (File exists)
rrdcached: daemonize failed, exiting.
Usage: zenrrdcached [run|start|restart|stop|status|stats] [options]
Daemon: zenhub is already running
Daemon: zenjobs is already running
Daemon: zeneventd is already running
Daemon: zenping is already running
Daemon: zensyslog is already running
Daemon: zenstatus is already running
Daemon: zenactiond is already running
Daemon: zentrap is already running
Daemon: zenmodeler is already running
Daemon: zenperfsnmp is already running
Daemon: zencommand is already running
Daemon: zenprocess is already running
Daemon: zredis is already running
Daemon: zenpython is already running
Daemon: zenjmx is already running

[root@localhost]# cd /opt/zenoss/var/

[root@localhost]# mv rrdcached.pid rrdcached.pid.old

[root@localhost]# service zenoss start

[root@localhost]# service zenoss status
Daemon: zeneventserver program running; pid=4058
Daemon: zopectl program running; pid=4164
Daemon: zenrrdcached program running; pid=20133
Daemon: zenhub program running; pid=4211
Daemon: zenjobs program running; pid=4278
Daemon: zeneventd program running; pid=4344
Daemon: zenping program running; pid=4410
Daemon: zensyslog program running; pid=4530
Daemon: zenstatus program running; pid=4513
Daemon: zenactiond program running; pid=4552
Daemon: zentrap program running; pid=4629
Daemon: zenmodeler program running; pid=4634
Daemon: zenperfsnmp program running; pid=4666
Daemon: zencommand program running; pid=4696
Daemon: zenprocess program running; pid=4728
Daemon: zredis program running; pid=4732
Daemon: zenpython program running; pid=4767
Daemon: zenjmx program running; pid=4800

Verify graphing now works.
Remove rrdcached.pid.old

[root@localhost]# rm rrdcached.pid.old