# ./vpnclient_init start
Starting /opt/cisco-vpnclient/bin/vpnclient: insmod: error inserting '/lib/modules/2.6.15-1.2054_FC5/CiscoVPN/cisco_ipsec.ko': -1 Invalid module format
I read elsewhere that this means it needs the linux headers, which would be the kernel-devel package. You can find out the kernel version you are running like this:
# uname -rm
I didn't know of an easy way to install automatically using yum since I'm not running the latest kernel version and yum wanted to install the newest package that doesn't match what I'm running. So...
I downloaded the kernel-devel rpm that I needed and then did a localinstall using yum:
yum localinstall kernel-devel-2.6.15-1.2054_FC5.i686.rpm
Did a reinstall of the Cisco vpnclient, ran the init.d start script as suggested by the installation notes, and - hooray! - it works again.
I'm running this version of the Cisco client, which was itself a pain in the ass to obtain because Cisco won't let me download it from them even though I've registered with them:
I guess I'll wait and see if I get to go through all this great fun again next time I update my kernel...