Error al compilar el kernel 2.4

["Enrique Factor" <efactor@amador.mir.es>]

Al intentar compilar el kernel 2.4 me da el siguiente error:
net/network.o: In function `ftp_nat_expected':
net/network.o(.text+0x30c26): undefined reference to `ip_nat_setup_info'
net/network.o: In function `delete_sack':
net/network.o(.text+0x31058): undefined reference to `ip_nat_cheat_check'
net/network.o: In function `help':
net/network.o(.text+0x31389): undefined reference to `ip_nat_cheat_check'
net/network.o(.text+0x3139c): undefined reference to `ip_nat_cheat_check'
net/network.o: In function `init':
net/network.o(.text.init+0x101f): undefined reference to
`ip_nat_expect_register'
net/network.o(.text.init+0x1032): undefined reference to
`ip_nat_helper_register'
net/network.o(.text.init+0x1045): undefined reference to
`ip_nat_expect_unregister'
make[1]: *** [vmlinux] Error 1
make[1]: Leaving directory `/usr/src/kernel-source-2.4.0'
make: *** [stamp-build] Error 2

¿Alguien sabe porque me pasa?

Saludos.