According to your logfiles, you changed the "Poller Interval" in Cacti from the default of "Every 5 Minutes" to "Every 10 Seconds".
The Cacti settings say:
The polling interval in use. This setting will effect
how often rrd's are checked and updated. NOTE: If you change this
value, you must re-populate the poller cache. Failure to do so, may
result in lost data.
This won't work unless you also change it in the system's cronjob!
Also we have the cron-interval, just below of it in the settings:
The cron interval in use. You need to set this setting
to the interval that your cron or scheduled task is currently running.
So, the question is: Do you really need 10-seconds sampling? REALLY? If not, revert everything to "Every 5 Minutes" and then go to "System Utilities -> Rebuild Poller Cache".
Restart cron, in case you made it not be be 5 minutes, and wait for 15 minutes. Graphs should be appearing then.
EDIT: Just saw your reply. Do not change crontab, it's ok.
Go to: "Settings -> Poller":
Set: Poller Interval = Every 5 Minutes
Set: Cron Interval = Every 5 Minutes
Go to: "System Utilities":
Run "Rebuild Poller Cache"
Do not fiddle around with intervals if you don't need to.