I'm a newb, so my method of approach is not suggested!
CentOS 5.5 Box:
1. Followed these instructions:
http://digitizor.com/2009/05/26/how-to- ... nux-guest/
2. Not all commands would work. Rebooted many times.
3. Followed your how-to. I used the yum instructions for Fedora. However, CentOS 5.5 says that dkms is not available via yum. Instead, I installed
dkms-2.0.20.2-1.noarch.rpm.
CentOS 5.4 Box:
1. Started with the how-to on this site.
2. Installed dkms RPM listed above. Additions kernel modules still wouldn't build. rebooted a few times.
3. Also followed these instructions posted in a forum on this site. Don't know if that matters...
yum install kernel sources
yum install kernel-devel
yum install gcc
ln -s /usr/src/kernels/2.6.18-92.1.18.el5-i686 /usr/src/linux
(reboot - modules still wouldn't build
reboot - worked on the 3rd try)
sh VBoxLinuxAdditions-x86.run
Works. YAY!
Hope that is helpful to someone!