Aaargh! What does this error message mean!

[Nevyn]

When I try and use Auto Levels on a 16 bit image in CS2 I get the following error message:
"Could not complete the auto levels command because the image cache is not deep enough"
Talk about a useless piece of feedback!
I don't get it when I use the command on 8 bit images, and if it's not supposed to work in 16 bit then why can I select it?
Does anyone know what this means and how I can "fix" it?

Thanks in advance...........

[ndsimm]

if you convert it to 8 bit and try the auto levels, does it work? how big are your scratch disks?
AFAIK, it could be a temp file or memory issue but I am no PS expert

[iCe]

Sounds like a memory problem. Just curious, why auto levels?

I just noticed that it's a long drive from my house to your house

[Nevyn]

It works when I convert to 8bit, but I want to try and avoid that since I'm starting with a raw file.
Could be scratch disks, I'll see if I can increase them and try again, thanks.

Memory. Hmm. Never been an issue before. Will think on that.
Why Auto Levels? It's just an easy way to improve contrast and reduce colour cast when processing some false colour IR images. It's part of the Levy process that Jerry has on his site. I don't use it for anything else, but it's still annoying to have to drop to 8 bit to use it.

Thanks for the suggestions guys.