trollboy@ubuntu:~$ cd /home/trollboy/vpn/vpnclient/trollboy@ubuntu:~/vpn/vpnclient$ sudo ./vpn_installCisco Systems VPN Client Version 4.0 (Rel) Linux InstallerCopyright (C) 1998-2001 Cisco Systems, Inc. All Rights Reserved.By installing this product you agree that you have read thelicense.txt file (The VPN Client license) and will comply withits terms.Directory where binaries will be installed [/usr/local/bin]Automatically start the VPN service at boot time [yes] noIn order to build the VPN kernel module, you must have thekernel headers for the version of the kernel you are running.For RedHat 6.x users these files are installed in /usr/src/linux by defaultFor RedHat 7.x users these files are installed in /usr/src/linux-2.4 by defaultFor Suse 7.3 users these files are installed in /usr/src/linux-2.4.10.SuSE by defaultDirectory containing linux kernel source code [] /usr/src* Binaries will be installed in "/usr/local/bin".* Modules will be installed in "/lib/modules/2.6.15-27-386/CiscoVPN".* The VPN service will *NOT* be started automatically at boot time.* Kernel source from "/usr/src" will be used to build the module.Is the above correct [y] yMaking moduleIn file included from linuxcniapi.c:14:/usr/include/linux/config.h:1:2: error: #error "Compilation aborted. Please read the FAQ for linux-libc-headers package."/usr/include/linux/config.h:2:2: error: #error "(can be found at http://ep09.pld-linux.org/~mmazur/linux-libc-headers/doc/)"In file included from linuxcniapi.c:25: