Problem installing guest additions on Centos 5.5 guest

[codfather]

OK, I get the following error when I run the VBLinuxAdditions.run on a 64 bit Centos 5.5 guest - the host by the way is Windows 7 (32bit) with VT extensions enabled in the BIOS. This is also running the latest Virtualbox 4.0.4 version - please note I have done this before many times with various guests/hosts.
The Error:
The headers for the current running kernel were not found. If the following
module compilation fails then this could be the reason.
The missing package can be probably installed with
yum install kernel-devel-2.6.18-194.32.1.el5

That rpm is however correctly installed - see below:

[root@bfs-VBOXADDITIONS_4.0.4_70112]# rpm -qa | grep kernel-devel
kernel-devel-2.6.18-194.el5

As is gcc, as required by chaper 4 of the Virtualbox documentation.

Here is what I get in the log file:

cat /var/log/vboxadd-install.log
Makefile:23: *** Error: unable to find the sources of your current Linux kernel. Specify KERN_DIR=<directory> and run Make again.. Stop.
Creating user for the Guest Additions.
Creating udev rule for the Guest Additions kernel module.

I have tried settng the KERN_DIR manually, but it then fails with an error about the kernel header directory, not being a directory, here is the line

export KERN_DIR=/usr/src/kernels/2.6.18-194.el5-x86_64

Now I have got the client kernel modules to compile manually, by uncompressing the 64 bit client code, and changing into the source directory and running "make" and "make install". I extracted the the source with the --keep --noexec parameters on the client additions file and I had to set the KERN_DIR manually to get this to work.

Any hints as to what might be going on here gratefully received, and any others who have tested this in a similar environment.

Cheers

Nick

[silvex]

Where did you get the guest additions for VB 4.0.4 ?

[codfather]

They came off the ISO file that came with that release.

[oilblue]

Couple things to check:

• double-check your kernel-devel version. kernel-devel-2.6.18-194.32.1.el5 is an update compared to kernel-devel-2.6.18-194.el5
• install dkms in the guest. Otherwise guest additions have to be reinstalled upon each time the guest's CentOS 5.x kernel is upgraded.

Hope that helps.