Zaptel- on FC5

hi to all
i m trying to install zaptel- on Fedora core 5 and getting the following error…
i had gone through and change kernal version but i m still getting this error…

[root@localhost zaptel-]# make
grep: /lib/modules/2.6.15-1.2054_FC5smp/build/include/linux/autoconf.h: No such file or directory
You do not appear to have the sources for the 2.6.15-1.2054_FC5smp kernel installed.
make: *** [all] Error 1

An immediate help would be highly appreciated…thanks