I can't compile the kernel

[Franco <cjimenezz@entelchile.net>]

I'm trying to compile the kernel (Debian way) but after 30 minutes
appears the following error:

depmod: ***Unresolved simbols in  
/usr/src/linux-2.4.20/debian/tmp-images/lib/modulos/2.4.20/kernel/drivers/net/wan/sis.o
depmod:   sis_malloc_Ra3329ed5
depmod:   sis_free_Rced25333
depmod:***Unaresolved simbols in
/usr/src/linux-2.4.20/debian/tmp-images/lib/modulos/2.4.20/kernel/drivers/net/wan/comx.o
make[2]: ***[modinst_post] Error 1
make[2]: Leaving directory /usr/src/linux-2.4.20
make[1]: ***[real_stamp_image] Error 2
make[1]: Leaving directory /usr/src/linux-2.4.20

What's the meaning of this?
Obviously the .deb file wasn't created