1. kbde-driver compilation failed.

In order to be compiled kernel module needs installed kernel sources.
As default make try to build kbde module for the current running kernel.

You may need to ajust it with make variable MODULE_KERNEL_VERSION or/and
install kernel sources.

If after that you got error again - most likely it's error from the linux
header's files. You have read it and try to understand what it say.

For example:

gcc kbde.c -c -D__KERNEL__ -DMODULE -I/usr/src/linux-2.4.21-199/include  -O2 -Wall 	
In file included from /usr/src/linux-2.4.21-199/include/linux/module.h:10,
                 from kbde.c:22:
/usr/src/linux-2.4.21-199/include/linux/config.h:4:28: linux/autoconf.h: No such file or directory
In file included from /usr/src/linux-2.4.21-199/include/linux/module.h:299,
                 from kbde.c:22:
/usr/src/linux-2.4.21-199/include/linux/version.h:6:2: #error "The kernel sources in /usr/src/linux are not yet configured."
/usr/src/linux-2.4.21-199/include/linux/version.h:7:2: #error "Please run 'make cloneconfig && make dep' in /usr/src/linux/"
/usr/src/linux-2.4.21-199/include/linux/version.h:8:2: #error "to get a kernel that is configured like the running kernel."
/usr/src/linux-2.4.21-199/include/linux/version.h:9:2: #error "Alternatively, you can copy one of the config files"
/usr/src/linux-2.4.21-199/include/linux/version.h:10:2: #error "arch/$ARCH/defconfig.* to .config, and run"
/usr/src/linux-2.4.21-199/include/linux/version.h:11:2: #error "'make oldconfig && make dep' to configure the kernel"
/usr/src/linux-2.4.21-199/include/linux/version.h:12:2: #error "for that configuration."
In file included from kbde.c:22:
/usr/src/linux-2.4.21-199/include/linux/module.h:301: parse error before "UTS_RELEASE"
In file included from /usr/include/asm/pda.h:4,
                 from /usr/src/linux-2.4.21-199/include/asm-x86_64/current.h:7,
                 from /usr/include/asm/current.h:4,
                 from /usr/src/linux-2.4.21-199/include/asm-x86_64/processor.h:19,
                 from /usr/include/asm/processor.h:4,
                 from /usr/src/linux-2.4.21-199/include/linux/wait.h:20,
                 from /usr/src/linux-2.4.21-199/include/linux/fs.h:12,
                 from kbde.c:23:
/usr/src/linux-2.4.21-199/include/asm-x86_64/pda.h:21: `CONFIG_X86_L1_CACHE_SHIFT' undeclared here (not in a function)
/usr/src/linux-2.4.21-199/include/asm-x86_64/pda.h:21: requested alignment is not a constant
In file included from /usr/include/asm/processor.h:4,
                 from /usr/src/linux-2.4.21-199/include/linux/wait.h:20,
                 from /usr/src/linux-2.4.21-199/include/linux/fs.h:12,
                 from kbde.c:23:
/usr/src/linux-2.4.21-199/include/asm-x86_64/processor.h:64: `CONFIG_X86_L1_CACHE_SHIFT' undeclared here (not in a function)
/usr/src/linux-2.4.21-199/include/asm-x86_64/processor.h:64: requested alignment is not a constant
/usr/src/linux-2.4.21-199/include/asm-x86_64/processor.h:305: `CONFIG_X86_L1_CACHE_SHIFT' undeclared here (not in a function)
/usr/src/linux-2.4.21-199/include/asm-x86_64/processor.h:305: requested alignment is not a constant

In this case kernel source is installed, but not configured.
So, you have to do what kernel need.

2. Compilation and install are fine, but modprobe can't find the module.
  (Reported by Brian Prestoll-Campbell for Mandrake 9.2)

Installation put module under
/lib/modules/$(MODULE_KERNEL_VERSION)/misc.

Two things may cause a problem:
- there is no module for the currently running kernel.
- modules directory is not in the modutil's search path.
  This path can be viewed with '/sbin/modprobe -c'.
  You have or change path in the /etc/modules.conf or move/copy module
  to the directory listed in search path