mount -t cifs failed but worked with the same kernel

I used a pre-built kernel from this image
debian-wheezy-7.2-armhf-3.8.13-bone30.img.xz (which is vmlinuz-3.8.13-bone30)

to make a new SD card for test purposes like in this tutorial:

I used this rootfs

And U-boot from git

Everything is working as expected (except zImage from debian-wheezy-7.2-armhf-3.8.13-bone30.img.xz is not on /boot partition like in tutorial) but at new linux, cifs always failed:

mount -t cifs // -o username=xxx,password=yyy /xp

mount error: cifs filesystem not supported by the system
mount error(19): No such device
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

Am I missing something? Since is the same kernel, cifs is enabled.
I installed cifs-utils. There is a strange error:

modprobe cifs

libkmod: ERROR …/libkmod/libkmod.c:554 kmod_search_moddep: could not open moddep file ‘/lib/modules/3.8.13-bone30/modules.dep.bin’

Any idea please?

Yeap... Stop mixing & matching random stuff.

If your going to use my rootfs from the eewiki, also setup the kernel
as also shown..