CentOS 5 :: Kernel Panic - Getting This"failed To Make Kdump Initrd" Messages At Startup."?

I've had a Centos 5.3 zimbra mailserver set up for about 3 months now.Every 7-10 days or so, the system will do a kernel panic and I've been putting off its resolution due to other matters.I'm now ready to look into it but I have two issues :

1) No logs.

So far, I've manually rebooted when a kernel panic occured and could look at the panic printout and write down relevant info. But since I wanted more info than I had written down, I went hunting in the logs for the kernel panic event (one happened earlier today) but, to my surprise, I noticed the system doesn't log the kernel panic at all. Kdump is currently disabled as I'd like to keep all available memory available to the system but I was under the impression it would log the kernel panic message regardless but would simply leave out more advanced diagnostic information.How would I make sure the kernel panic is logged so I can have more info about it ?

2) The actual panic.Here's a snippet of what's appearing when the kernel panics :

EIP c0467136 page_remove_rmap+0x66/0xc0 SS:ESP 0068:c3ca6ddc <0> Kernel panic - not syncing: Fatal Exception

I've also seen f793bee4 instead of the highlighted part above but everything else is always the same from the times I've seen (as I haven't always had the chance to be around when a panic occured).I'm looking further into it at this point but early research seem to indicate this could be a memory issue. I'll run memtest next weekend to check that out (since I don't want to take the system offline for any length of time during office hours) but people here might have other theories based on what I've put up so far. The system has all of the latest patches and updates and is running only what I need as far as software goes (zimbra server + prerequisites, x + GNOME (not loaded on startup), firefox and vnc for windows RDP access). My system also uses a software RAID1 array (boot = md0 and / = md2 with swap files not being mirrored as there's no need to).

PS : In order to further troublehsoot by myself before posting here, I've tried to enable kdump to see if kdump is the culprit for the missing logs but I'm also having an issue with it. I'm getting a "No kdump initial ramdisk found" and "mkdumprd: failed to make kdump initrd" messages at startup. I'm thinking this might be because of my raid array ? I've found an old bug report regarding one of those error messages on centos 5.2 but it was supposedly fixed in the 30 version by RH and I'm using the latest one (56).