When you publish to DITA, make sure all of your settings are configured correctly.
Your content should use plain files that don't use any external HTM files. For example, if your TOC uses the DHTML option and the media object uses an external HTM file, you receive an error that looks like:
Invalid DITA for 'toc.htm'. Please check templates are valid XHTML. See log for more details.
Finalizing DITA (3 Second(s))
Publishing failed due to an Error: Access to the path '\\Program Files\Author-it\Publishing\DITA\X1000 User Guide' is denied.