[AUCTeX] Preview problems when using a certain document class

[Mark Jago]

I just changed document class to lipics (class files at
http://drops.dagstuhl.de/styles/lipics/lipics-authors.tgz) which is
used for various conference proceedings, i.e.

\documentclass[a4paper,UKenglish]{lipics}

I now have problems rendering previews in AUCTeX. Sections and display
formulas are not rendered. In Emacs I get this little red circle with
a white horizontal bar. Inline formulas on the other hand are rendered
correctly. I have no idea how to tweak AUCTeX to cope with the lipics
document class. Rendering the whole pdf with pdflatex is no problem,
so the source file is certainly fine.