I’m getting an error running the xhtml converter from the Windows command line (running Windows 7). It completes but then I get a dialogue box that LibreOffice has stopped working. After debugging it seems the problem could be that it needs to access the mscoree.dll associated with the pertinent .Net version.
This is strange, the xhtml converter is AFAIK a set of XSLT stylesheets interpreted by LibO’s internal XSLT processor. If any part of LibO interacts with a .Net library, I don’t see why this should be related to XSLT execution… Have you tried running other tasks from the command line? If another task returned the same error, then you could at least suppose that the problem is not specific to XSLT processing.