Buildworld problem?

[Java Weenie]

I had a 4gig drive laying around that I wanted to use for a router, so I 
installed the latest (from about 1.5 weeks ago) from the 5.x distrubutions.  
I added ipfw/natd/dummynet to the kernel file and did a full buildworld, 
buildkernel.  I rebooted after install kernel, everything seemed normal, did 
install world/mergemaster, rebooted.  Right now, I have an 'ok' prompt, it 
appears after the 'Press enter to start booting immediately, or hit any 
other key to <do something else>' option and it states it cannot find kernel 
or kernel.old.

My guesses are that either I got a really bad batch of sources, I performed 
a buildworld wrong (though I did double check my steps with the handbook 
first), or my hard drive picked a really unusual place to die.

It is a new clean install so it wouldn't be a huge issue to reinstall, but 
if it is hardware, I will need to replace the drive before doing this again.

Any thoughts on how to determine the problem?

Thanks for any tips.