How to build dm-raid4-5 module ?

Hello,

i am trying to build this dm-raid4-5 kernel module to get my nvidia
raid5 running. I´ve downloaded, patched und build kernel 2.6.15.4. After
changing the Makefile it compiles dm-raid4-5, but i´m getting errors
like there are some things not included. I can post a more detailed
report later, but may someone can tell me the way to build this module.
Greetings,

Ralph