The installation of slitaz you installed linux-media on has critical missing or broken files.
I have no errors installing linux-media and uvcvideo kernel module loads with no error.
root@slitaz:/home/tux# tazpkg -gi linux-media
Installation of package "linux-media"
================================================================================
The Linux kernel media modules.
--------------------------------------------------------------------------------
Copying package... [ Done ]
Extracting package... [ Done ]
Installing package... [ Done ]
Removing all tmp files... [ Done ]
Execute post-install commands... [ Done ]
================================================================================
Package "linux-media" (3.2.71) is installed.
root@slitaz:/home/tux# modprobe -v uvcvideo
insmod /lib/modules/3.2.71-slitaz/kernel/drivers/media/media.ko.xz
insmod /lib/modules/3.2.71-slitaz/kernel/drivers/media/video/videodev.ko.xz
insmod /lib/modules/3.2.71-slitaz/kernel/drivers/media/video/uvc/uvcvideo.ko.xz
root@slitaz:/home/tux# lsmod | grep uvcvideo
uvcvideo 46650 0
videodev 56659 1 uvcvideo
media 6541 2 uvcvideo,videodev
root@slitaz:/home/tux# modinfo uvcvideo
filename: /lib/modules/3.2.71-slitaz/kernel/drivers/media/video/uvc/uvcvideo.ko.xz
version: 1.1.1
license: GPL
description: USB Video Class driver
author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
srcversion: 6AB3280B231D832D507E9F5
alias: usb:v*p*d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v1C4Fp3000d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v1B3Bp2951d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v19ABp1000d00*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v19ABp1000d01[0-1]*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v19ABp1000d012[0-6]dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v199Ep8102d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v18ECp3290d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v18ECp3288d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v18ECp3188d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v18CDpCAFEd*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v1871p0306d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v17EFp480Bd*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v17DCp0202d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v174Fp8A34d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v174Fp8A33d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v174Fp8A31d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v174Fp8A12d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v174Fp5931d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v174Fp5212d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v152Dp0310d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v13D3p5103d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v0E8Dp0004d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v0AC8p3420d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v0AC8p3410d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v0AC8p332Dd*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v06F8p300Cd*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v05E3p0505d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v05C8p0403d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v05ACp8501d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v05A9p7670d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v058Fp3820d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v04F2pB071d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v046Dp08C7d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v046Dp08C6d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v046Dp08C5d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v046Dp08C3d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v046Dp08C2d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v046Dp08C1d*dc*dsc*dp*icFFisc01ip00*
alias: usb:v045Ep0723d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v045Ep00F8d*dc*dsc*dp*ic0Eisc01ip00*
alias: usb:v0458p706Ed*dc*dsc*dp*ic0Eisc01ip00*
depends: videodev,media
intree: Y
vermagic: 3.2.71-slitaz SMP mod_unload 386
parm: clock:Video buffers timestamp clock
parm: nodrop:Don't drop incomplete frames (uint)
parm: quirks:Forced device quirks (uint)
parm: trace:Trace level bitmask (uint)
parm: timeout:Streaming control requests timeout (uint)