[root@localhost zaptel-1.2.9.1]# make
grep: /include/linux/autoconf.h: No such file or directory
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE   -c -o gendigits.o gendigits.c
cc -o gendigits gendigits.o -lm
./gendigits > tones.h
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE    makefw.c   -o makefw
./makefw tormenta2.rbt tor2fw > tor2fw.h
Loaded 69900 bytes from file
./makefw pciradio.rbt radfw > radfw.h
Loaded 42096 bytes from file
ZAPTELVERSION="SVN-branch-1.2-r1468" build_tools/make_version_h > version.h.tmp
if cmp -s version.h.tmp version.h ; then echo; else \
        mv version.h.tmp version.h ; \
fi

rm -f version.h.tmp
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE   -c -o ztcfg.o ztcfg.c
cc -c -fPIC -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DBUILDING_TONEZONE -o zonedata.lo zonedata.c
cc -c -fPIC -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DBUILDING_TONEZONE -o tonezone.lo tonezone.c
ar rcs libtonezone.a zonedata.lo tonezone.lo
cc -o ztcfg ztcfg.o libtonezone.a -lm
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE   -c -o torisatool.o torisatool.c
cc -o torisatool torisatool.o
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE   -c -o ztmonitor.o ztmonitor.c
cc -o ztmonitor ztmonitor.o
cc -o ztspeed.o -c ztspeed.c
cc -o ztspeed ztspeed.o
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE   -c -o zttool.o zttool.c
cc -o zttool zttool.o -lnewt
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE    zttest.c   -o zttest
cc -I. -O4 -g -Wall -DBUILDING_TONEZONE    -DSTANDALONE_ZAPATA -DZAPTEL_CONFIG=\"/etc/zaptel.conf\" -DHOTPLUG_FIRMWARE   -c -o fxotune.o fxotune.c
cc -o fxotune fxotune.o -lm

You do not appear to have the sources for the 2.6.9-42.ELsmp kernel installed.
make: *** [linux26] Error 1