[Baol-hth-list] string-width error

[Brian J. Lopes]

Hey everyone,
I have a quick question.  I'm using emacs 19.34.1, and I just upgraded to
the current beta version of html-helper.  I was hoping to get better
support for tables in html.  Anyway, now I'm getting the following error
when emacs opens a web page.

Loading html-helper-mode...
File mode specification error: (void-function string-width)

Can someone please help me with this.  I've googled it, and it seems like
nobody else has had this problem.

Thanks