The ipg script provided by net-misc/iputils is outdated: The module isn't called pg3 anymore and the location in /proc/net has changed.
Created attachment 44280 [details, diff] Patch for ipg Patch against /usr/src/linux/Documentation/networking/pktgen.txt (2.6.9 vanilla).
actually, the script should be re-written to support either there's no telling what kernel the user will try to use the script on
Yes, that would be the best solution.
made ipg a little more dynamic and fixed in cvs