xemacs and html

[Adam Read <adam@cr888087-b.bloor1.on.wave.home.com>]

When I try to edit html in xemacs I'm getting the error:

External entity HTML not found
  Public identifier -//W3C//DTD HTML 4.0//EN

I've tried other doctypes, but I just get the same error with whatever I replace "-//W3C...//EN" with.

My syntax highlighting is now all messed up, and indenting has gone all wrong.  I've tried using html-helper-mode.  The syntax highlighting is right with that, but it apparently doesn't do indenting.  

I'm using xemacs 21.1.14-1 on a pure unstable box.

Thanks for any help,

Adam