[CentOS] ERROR Installing Cisco AnyConnect on Centos 6x

Wed Sep 30 18:28:55 UTC 2015
CS DBA <cs_dba at consistentstate.com>

Hi All;

I've downloaded the Cisco AnyConnect tar.gz file for one of our clients, 
when I untar it and then run the vpn_install script in the vpnclient 
directory I  get the below error.

Thanks in advance for any help...

//# ./vpn_install//
//Cisco Systems VPN Client Version 4.8.02 (0030) Linux Installer//
//Copyright (C) 1998-2006 Cisco Systems, Inc. All Rights Reserved.//
//By installing this product you agree that you have read the//
//license.txt file (The VPN Client license) and will comply with//
//its terms.//
//Directory where binaries will be installed [/usr/local/bin]//
//Automatically start the VPN service at boot time [yes]//
//In order to build the VPN kernel module, you must have the//
//kernel headers for the version of the kernel you are running.//
//Directory containing linux kernel source code 
//* Binaries will be installed in "/usr/local/bin".//
//* Modules will be installed in 
//* The VPN service will be started AUTOMATICALLY at boot time.//
//* Kernel source from "/lib/modules/2.6.32-573.7.1.el6.x86_64/build" 
will be used to build the module.//
//Is the above correct [y]//
//Making module//
//make -C /lib/modules/2.6.32-573.7.1.el6.x86_64/build 
SUBDIRS=/root/vpnclient modules//
//make[1]: Entering directory `/usr/src/kernels/2.6.32-573.7.1.el6.x86_64'//
//scripts/Makefile.build:49: *** CFLAGS was changed in 
"/root/vpnclient/Makefile". Fix it to use EXTRA_CFLAGS.  Stop.//
//make[1]: *** [_module_/root/vpnclient] Error 2//
//make[1]: Leaving directory `/usr/src/kernels/2.6.32-573.7.1.el6.x86_64'//
//make: *** [default] Error 2//
//Failed to make module "cisco_ipsec.ko".//