buildroot and linux-2.6.17 to 2.6.20

hello i try to build with linux 2.6.18.2 and (2.6.20) patched proposed by wiki.

under buildroot http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif

it goes well until menuconfig end, after an error on this line

SPLIT include/linux/autoconf.h -> include/config*

no such file

how to get the correct file in linux2.6.x/scripts/basics ?

how to generate the corresponding file ?