Plone: Correcting Page Template Errors Easily
Here’s how to correct pesky problems in your code/XHTML since the line number and column references are slightly useless in the ZMI.
Paste contents from a page or page template from the ZMI into a program like gedit and then the line and column reference numbers will be correct (once you remove the comment about the error from the top of the page).
Editing in the ZMI is a bit painful, but we persevere.