can't find function "submatch"

[Steve Yegge]

I am running GNU Emacs 24.1.50.3 (x86_64-unknown-linux-gnu, GTK+ Version 2.20.1) of 2012-05-15

I unzipped nxhtml-2.08-100425.zip into ~/emacs/site-lisp/ and added ~/emacs/site-lisp/nxhtml/ to my load path.

I then did a M-x load-file "~/emacs/site-lisp/nxhtml/autostart.el", which yielded the following error:

Loading /home/stevey/emacs/site-lisp/nxhtml/autostart.el (source)...
Nxml/Nxhtml Autostart.el loading ...
Loading /home/stevey/emacs/site-lisp/nxhtml/etc/schema/schema-path-patch.el (source)...done
Loading /home/stevey/emacs/site-lisp/nxhtml/nxhtml-loaddefs.el (source)...
rx: Symbol's function definition is void: submatch

I searched around and did not find a definition of a function called `submatch' anywhere.