nautilus: No built-in viewers work

[Toralf Lund <toralf kscanners com>]

Image, text and HTML-view in Nautilus fail on my Red Hat 7.1 system.
When I double click on a file's icon, I get a dialogue box with the
message

     The Image view encountered
     an error while starting up.

(for images; a very similar message is printed for plain text or HTML.)
I have tried "Raw Hide" binary RPM as well as a version I've built from
CVS, with the same result.

Any ideas what may be wrong? How do I go about investigating the problem
further? And who wrote this bloody useless error message???

- Toralf