Edited Unassigned: Javascript errors with Ajax 15.1 HTMLEditorExtender [27824]

I'm receiving several javascript errors in ScriptResource.axd files when adding an HtmlEditorExtender to my page. These are VERY concerning as I cannot find any information on the web. I've had numerous problems with Ajax controls before and I thought things were sorted out in v15.1.

Screenshot of Error 1.bmp shows the error when my page loads. The line of code is attempting to set a width property. Screenshot of Locals.bmp shows the values of locals.