DHTMLXspreadsheet Drupal plugin: sheet not rendered

I have installed the dhtmlxSpreadsheet plugin on a Drupal 7.12 site and when inserting a spreadsheet it generates the following error:

I followed the guide to install and use found here:
docs.dhtmlx.com/doku.php?id=dhtm … ide_drupal

When the page is saved and viewed the javascript to load the spreadsheet is rendered as plain text as opposed to wrapped in a tag to actually be executed by the browser. Is this a configuration issue or a incompatibility with Drupal 7.12?

(I realize this is the dhtmlxGrid section but it appears that there is not a separate section for the spreadsheet product.)