Are you using the "Oleg Scripts" for graph generation?

I believe there is a few things that need to be changed.

I can take a look and see if I can find the scipts I once had working in OpenWrt

Ok.

I will try to take a look at it. Maybe even install rrdtool on my own router to see if I can make it work.

Hello Pjotrek :-)

I have the same problem on my old Netgear WGT634U, which is running OpenWGT in the meantime.
Collecting data works, but it hangs forever generating the graphs :-(
I have a wild mixture of packages for Olegs ASUS firmware and various packages for OpenWrt on it (OpenWGT is very bare bones :-(( ), and I thought it might be an incompatibility between some of them.
In my opinion, the scripts are OK, it's a problem with the binaries.

But anyway, OpenWGT is much more stable than the original Netgear firmware (with the exception of the wireless part, which I disabled entirely, because I don't need it there).

On my WL-500gx I have rrd statistics for traffic, CPU load & CPU usage generated on demand via CGI scripts. I had to switch to thttpd without php, because the CGI timeout  in the php version  of 30 secs is not enough to generate the graphs dynamically. 
The difference is huge, before the conversion to CGI, the router had a nearly constant cpu usage of 60%, now it's below 5%.

Anybody interested?

greetings from Vienna
Martin

P.S. Is it true that ASUS discontinued the production of the WL-500gx? Maybe we should try to get some units before the are sold out everywhere?

MMCM solution moved to new topic in the OpenWrt forum.

I just moved it to the correct location.

That might help the popularity that people actuately do see it :-)