Thanks very much, Ongte! Where does the kernel source file supposed to be located? There are files like "modules.usbmap, modules.symbols, etc" in the /lib/module/2.6.26-2-686/kernel folder. Actually, I did try to change the path of Kernel source pointing in the Makefile source code:
"KERNEL_SRC ?= /lib/modules/$(KERNEL_VERSION)/build" from "build" to "kernel"
However, I still got similar error message as bellow:
make -C /lib/modules/2.6.26-2-686/kernel M=/opt/EFCS/MURTC/module KBUILD_VERBOSE=1 modules
make: Entering directory `/lib/modules/2.6.26-2-686/kernel'
make: *** No rule to make target `modules'. Stop.
make: Leaving directory `/lib/modules/2.6.26-2-686/kernel'
make: *** [murtc.o] Error 2
the only difference is it entering the directory.