RRD Graphs in NodeWorx have broken
From Ubiquity Server Wiki
The RRD graphs seen throughout InterWorx rely on the cron daemon to continue working. If at any point they stop working, you'll want to make sure that the cron daemon is in fact running. The best starting course of action is simply to restart the cron daemon from shell.
service crond restart
If you continue to have problems, contact Ubiquity support and we can either help fix the issue, or contact InterWorx priority support on your behalf.
