If you make a mistake in your CAML query, you just get the obscure error “one or more fields are not installed properly”
Sometimes it can be something as simple as failing to close and <and> tag. For me, I was querying on a field with a space in the name.
I should have known this!
http://www.delphi-ts.com/blogs/lozzi/post/2009/05/14/CAML-Gotchas-in-SharePoint.aspx
