"Install script not found" on Firefox 1.0.4?!

"Paul Schmidt" <[email protected]> Fri, 15 Jul 2005 10:42:16 -0400

Newsgroups	gmane.comp.mozilla.devel.xpinstall
Organization	Another Netscape Collabra Server User
Message-ID	<[email protected]>

My install.rdf is based on a number of sources, but most closely from 
"Packaging Firefox/Thunderbird Extensions" by Ben Goodger, updated by 
Benjamin Smedberg 3/1/05. It all looks clean, but when I try to install the 
xpi in Firefox 1.0.4, it complains "Install script not found". The 
documentation I have clearly states that "install.js scripts are no longer 
used for Firefox...", referring to version 0.9 and newer.

Is this actually true, or do I have some subtle bug that triggers this 
message erroneously?