What is causing this failure when using readHTMLTable()?

library(XML)
url <- 'http://www.dqnews.com/Charts/Monthly-Charts/LA-Times-Charts/ZIPLAT.aspx'
tableVals <- readHTMLTable(url)

When I run this all by itself on a fresh workspace, I get

Error: Namespace prefix  of attribute publishsource is not defined

After digging through the page source, the closest attribute I found to the one in the error is this:

`<div id="Chart for Web_9726" align="center" x:publishsource="Excel">`

but searching turns up nothing. Is there perhaps a better way to automatically vacuum this data into a matrix o开发者_运维百科r dataframe?