9.2-RC1: Problem with Kernel

[Walter Hurry]

This is 9.2-RC1 on amd64 (upgraded from 9.2-BETA1 by refetching the 
source from releng/9.2 and rebuilding kernel and world).

The kernel compiles and runs fine using the supplied GENERIC, but when I 
try to use my custom kenel config file, on reboot I get this:

Mounting from ufs:/dev/ada0p2 failed with error 19

What module(s) have I missed?

Thanks.