MOSS 2007 "File Not Found" error - chris

Hi - -

When I hit any page under _layouts, I get a page which reads "File Not
Found".  In the Event Log, I have the following:

Load control template file /_controltemplates/UserFieldEditor.ascx
failed: Could not load the assembly
'Microsoft.SharePoint.ApplicationPages'. Make sure that it is compiled
before accessing the page.

There a a bunch like that.  Then I have this:

Error: Failure in loading assembly: Microsoft.SharePoint.Portal,
Version=11.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c

Which seems odd given that I'm using 2007.  Can anyone shed some light
on this?  Thanks.

chris