DOCBOOK-APPS: WebSite DTD Error

I am wondering if there's problem with Website DTD. When I edit a 
website.xml with website.dtd within Emacs+psgml environment, and tried 
to add an element with Markup->Insert Element, there's an error saying 
"Delimiter GRPC ()) expected; at: :input|html:," which was caused by 
para.char.mix. I read carefully website.dtd, and there seems no 
problems. Then I tried to comment out some entity declaration which I 
think can work around the problem. But the same error message appeared.

Did I miss something? I edit xml document with either docbook or 
simplified docbook for awhile and no problem at all with my Emacs 20.x + 
RedHat 7.2. What problem with website?

Thanks for any help!

Sidney Lu
Academia Sinica Computing Centre
Taipei. Taiwan