Before installing module-init-tools.tcz:
hash -r; type modprobe
modprobe is /sbin/modprobe
After installing module-init-tools.tcz:
hash -r; type modprobe
modprobe is /usr/local/sbin/modprobe
In given context this implies that your PATH and extension both seem to work fine as expected, but that there is a hardcoding bug in the software you try to run as already hinted in Reply #4.
After adding alias:
hash -r; type modprobe
modprobe is /usr/local/sbin/modprobe
Ah, yes, this is expected, what would be relevant instead would be:
type /sbin/modprobe
type /sbin/modprobe gives me /sbin/modprobe is /sbin/modprobe
I'll go ahead and submit a request to not have modprobe hard-coded.