[DRBD-user] DRBD module won't load

[Wood.Chris at tatravelcenters.com]

Hello

I'm trying to start drbd on an Oracle Virtual Server (Xen) machine. I get 
this error:

Starting DRBD resources: Can not load the drbd module.

I have these packages installed

$ rpm -qa|grep drbd
drbd-pacemaker-8.3.6-1.el5
drbd-bash-completion-8.3.6-1.el5
drbd-8.3.6-1.el5
kmod-drbd-8.0.16-5.el5_3
drbd-utils-8.3.6-1.el5
drbd-xen-8.3.6-1.el5
drbd-heartbeat-8.3.6-1.el5

/etc/drbd.conf
global {
        usage-count no;
}
common {
        protocol C;
}
resource r0 {
  disk {
        fencing resouce-only;
  }
  handlers {
        fence-peer "/usr/lib/drbd/crm-fence-peer.sh";
        after-resync-target "/usr/lib/drbd/crm-unfence-peer.sh";
  }
  syncer {
        rate 40M;
  }
  on admin-lab-ovs0 {
        device  /dev/drbd0;
        disk    /dev/sda3; 
        address 10.98.4.90:7789;
        meta-disk       internal;
  }
  on admin-lab-ovs1 {
        device  /dev/drbd0;
        disk    /dev/sda3; 
        address 10.98.4.91:7789;
        meta-disk       internal;
  }
}

My kernel is Linux 2.6.18-128.2.1.4.9.el5xen #1 SMP Fri Oct 9 14:57:31 EDT 
2009

Here are the messages from the log

Mar 17 13:06:09 admin-lab-ovs0 modprobe: FATAL: Module drbd not found. 
Mar 17 13:08:44 admin-lab-ovs0 modprobe: FATAL: Module drbd not found. 
Mar 17 13:18:02 admin-lab-ovs0 yum: Installed: 
kmod-drbd-8.0.16-5.el5_3.i686
Mar 17 13:20:27 admin-lab-ovs0 modprobe: FATAL: Module drbd not found. 
Mar 17 13:21:12 admin-lab-ovs0 kernel: drbd: disagrees about version of 
symbol struct_module
Mar 18 04:42:24 admin-lab-ovs0 modprobe: FATAL: Module drbd not found. 

Any help would be much appreciated - do I have to build the module from 
scratch?

Thanks,
Chris