In the sqm-scripts package for managing network traffic shaping is this line for finding a program suitable for loading the kernel shaping modules:
[ -z "$INSMOD" ] && INSMOD=$(which modprobe) || INSMOD=$(which insmod)
It seems to set INSMOD to /usr/sbin/insmod, even though /usr/sbin/modprobe is available. (Both are symlinks to ../bin/kmod.)
According to this article, the return value of the first assignment should be success and it shouldn't take the fallback statement:
Also working the issue here: