Interface Graphs are no longer displayed

[Xoogle]

Hello everybody,
I'm looking for some help with cacti. I would like to show the characteristics of bandwidth on my switch devices.
It worked for some weeks but now some settings were changed and the interface can't be monitored anymore.
Maybe you can advice me were I can fix this problem.

Any Ideas ?

thanks.

[micke2k]

What changed?

Check cacti.log and post it.