hi, to fix this problem simply copy the attached file (libipt_standard.so) in this bug report
http://bugs.endian.it/view.php?id=2943to your EFW 2.4 firewall into the following directory
/lib/iptables/
EDIT: do also set the same rights to the file as the other files do have in this directory.
Then restart your server and the Traffic Graphs should work again.
It's unfortunately typical that Endian has already fixed that problem and do not release a update through efw-upgrade... it's a shame!!
NicoP.