If your trying to insert a kernel module (insmod) after compiling it and get the error below:
insmod: error inserting 'arcmsr.ko': -1 Unknown symbol in module
Then you may not have loaded the modules that module depends on. In the example the arcmsr.ko is a raid scsi driver. But the scsi subsystem modules were not loaded before the scsi raid driver was inserted. So it failed with the error message. You would need to modprobe for the scsi devices modules first.
Then insert the raid driver module.
To get a scsi raid driver to load on boot do the following. The example is for a scsi raid dirver from Areca compiled with the name arcmsr.ko. Get the raid (scsi) driver and make it. Take the made driver (for example arcmsr.ko) and copy to current kernel modules dir.
cp arcmsr.ko /lib/modules/`uname -r`/kernel/drivers/scsi/
Put "alias" line below in file /etc/modprobe.conf
echo alias scsi_hostadapter arcmsr >>/etc/modprobe.conf
Update a the lists the dependencies for every module.
Make the new initrd image and copy it into boot directory
mkinitrd -f -v /boot/initrd-`uname -r`.img `uname -r`
The above mkinitrd line is for CentOS 5 kernel. Your kernel name may be different. Also, note you might need --with=sd_mod --with=scsi_mod in mkinitrd line. Since the raid module is dependent on these. Try it without them first. Don't forget to change your /boot/grub/menu.lst file to reflect the new initrd image name if need be.