Intermittent failure to automatically include all models

I have two models in my rails app that inherit from ValidatingBase
instead of ActiveRecord. I didn’t start having this issue until I
switched to Planet Argon, running lighttpd, but I’ve started to get
errors where one or the other models doesn’t get included and I get an
“uninitialized constant ModelName” error. The weirdest thing is that
when I restart lighty it sometimes includes one of the models and
sometimes the other model, so my errors seem to vary. Has anyone seen
this before? Is there a way I can make my app load certain models
explicity to avoid this bug?

Thanks,
Carl