AS, i`ll go through step by step what i have done so far.
created a directory # mkdir kernel-2.6.y
then i moved the file to that folder
Extract the files into the new directory.
now the files that should be in that folder are: sierra.c, sierra_net.c, Makefile, usbnet.h  , skb_compat.h .
those last 2 files are not in that folder nor could i find them on my system, maybe this is where it is not working right ?
I won`t go any further until i see what you think about those last 2 files.