This is a known problem with RHEL/CentOS and Fedora. They constantly patch in future kernel enhancements with dated/stable version kernels. Which makes compiling against their kernel-devel package a nightmare.
I have made some precompiled RPMs that address this situation and they are available at
http://rpm.fugitol.com.
For Zaptel on CentOS/EL 5 specifically (x86),
http://rpm.fugitol.com/el/5/i386/zaptel12-1.2.20.1-5.el5.fio.i386.rpm.
For yum repo instructions, goto
http://www.fugitol.com.
A "yum groupinstall Vicidial" will install all the prereqs and and optional packages listed in the SCRATCH_INSTALL. DO NOT do this on an existing system, as it will most likely screw up your install, or it may work fine...I will not be held responsible. It should be pretty stable for installing on a new system...I have done it this way for my last 2 production systems.
Any flames and/or problems with these repositories should be directed to me at lottc AT fugtiol DOT com. CentOS/RHEL/Fedora are NOT supported by the VICIDIAL or eflo teams!!! So do not post problems to these forums...especially regarding my RPMs The official linux flavor of VICIDIAL is Slackware.
I will continue to maintain these RPMs as Redhat based systems are what I prefer to use...However, if you want/need support with aspects outside of VICIDIAL, like Zaptel or Asterisk, you should be using Slackware.
-Lott