rrd's no longer created for SOME snmp data

[stclam]

Hi All,
I've got a wierd problem. rrd's for interface data can no longer be created.
Using cacti 0.8.6h polling a cisco router for CPU can be setup fine. But attempting to graph an interface will not create the rrd file.

All existing graphs/rrd's are working fine. (BTW this seems similar to http://forums.cacti.net/post-70049.html )

Has anyone any clues ?
I's also love opions as to what is the most efficient way to debug the php scripts behind the web interface.

[gandalf]

First, change "Settings -> Logging Level" to DEBUG for one polling cycle and check cacti.log
Reinhard