I am trying to install the Cisco VPN client on Fedora Core 5.... When installing, the installation script requests the path to the kernel source directory... (see below) I'm uncertain what path to give. I'm sure this is a simple answer that I should know but I'd appreciate help. Thanks...

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.

For RedHat 6.x users these files are installed in /usr/src/linux by default
For RedHat 7.x users these files are installed in /usr/src/linux-2.4 by default
For Suse 7.3 users these files are installed in /usr/src/linux-2.4.10.SuSE by default

Directory containing linux kernel source code []

=============================================

I've tried several directories that looked right but no luck.

Thanks..

well I guess you dont have the kernel headers installed.
try
yum install kernel-devel

Actually, I did that yesterday.

/usr/src/redhat/BUILD/kernel-<version>/linux-<version>

whats the output of
rpm -q kernel-devel
and
uname -a

answering both of the above suggestions:

/usr/src/redhat/BUILD is an empty directory. I still tried it but the install fails.

Here are the outputs from the two commands requested.
kernel-devel-2.6.17-1.2187_FC5

Linux fedora.htc.net 2.6.15-1.2054_FC5 #1 Tue Mar 14 15:48:33 EST 2006 i686 i686 i386 GNU/Linux

Thanks for the help:

as you can see you have a kernel version of 2.6.15-1.2054_FC5 and kernel-devel version 2.6.17-1.2187_FC5, which are not same. upgrade your kernel and it should solve your problem.
yum install kernel, should do it.

That was the missing piece. Thanks all for your help. It's much appreciated.