FC6 and CISCO VPN Client

[Alessandro Brezzi]

Hi all,
after a fresh install and full update of FC6, I'm unsuccesfull in
installing CISCO VPN Client
vpnclient-linux-x86_64-4.8.00.0490-k9.tar.gz in my AMD64 box:

make -C /lib/modules/2.6.18-1.2798.fc6/build SUBDIRS=/root/vpnclient modules
make[1]: Entering directory `/usr/src/kernels/2.6.18-1.2798.fc6-x86_64'
  CC [M]  /root/vpnclient/linuxcniapi.o
/root/vpnclient/linuxcniapi.c:12:26: error: linux/config.h: No such
file or directory
In file included from /root/vpnclient/Cniapi.h:15,
                 from /root/vpnclient/linuxcniapi.c:27:
/root/vpnclient/GenDefs.h:110:2: warning: #warning 64 bit

yum list 'kernel*'  return:
.....
Installed Packages
kernel.x86_64                            2.6.18-1.2798.fc6      installed
kernel-devel.x86_64                      2.6.18-1.2798.fc6      installed
kernel-headers.x86_64                    2.6.18-1.2798.fc6      installed
....
So, what I've missed?
Thank to all in advance
-- 
Alessandro Brezzi