Unresolved Symb...in 2.4.12 ehci installation

I have upgraded my Linux 7.1 (kernel version 2.4.2) to kernel version
2.4.12. I want to install the linux ehci driver as well. On applying the
required changes in the usr/src/linux/drivers/usb/Makefile and
usr/src/linux/drivers/usb/Config.in files and selecting the EHCI as a
module in make menuconfig. When i get to the part where i do make
modules_install after make modules, i get the following error:-

depmode: *** Unresolved Symbols in
/lib/modules/2.4.12/kernel/drivers/usb/usbcore.o
depmode: usb_hub_cleanup
depmode: usb_hub_init

I have tried to install the same with and without the kernel version info
but to no avail. Shall be grateful if anybody could advise! Thanking you in
advance.

Kashif!