samba expects to find smbmnt in /usr/bin. Unfortunately, it doesn't seem to
check your path for it, so adding /usr/sbin to your path won't fix the problem.
The quick fix is (obviously) symlinking /usr/sbin/smbmnt to /usr/bin/smbmnt
root@rux0r root # strings /usr/bin/smbmount | grep smbmnt
execvp of smbmnt failed. Error was %s.
smbmnt failed: %d
root@rux0r root #
this may have once been valid but it no longer is, so closing bug