Empty graphs for new devices

[fugtruck]

I have a cacti installation that has been working fine. Recently, I added several new devices + graphs and that batch of devices the graphs are all blank. The devices are linux hosts and the graphs are Data In/out bits for the host network adapters. A verbose query from the devices returns correct information about the host. I know this will be a vague question but can anyone give me some suggestions as to where to look? I have these new hosts configured similarly to existing hosts and am just not seeing any errors, but still I have no graphs.

[fugtruck]

I think I might have figured it out. The .rrd files weren't generating because of a permissions problem.