Zero scoring transformation attempted

[joncard]

I am attempting to control content in a templated website using Alfresco. One of the requirements is that the content be composed off-line, so I'm designing this so that users can compose content in Word, then import that content to a space that will transform the content into HTML using Open Office and then transform it into XHTML with "tidy" so that I can access the content through an XSLT template to strip out the html tag wrapping, the whole head tag, the body tag wrapping, etc., so I can include the HTML fragment in the MyFaces web site.

I've followed the instructions here:
http://wiki.alfresco.com/wiki/Content_Transformations
for installing a "tidy" transformer and will someday upgrade so that these two transformation happen at once in complex transformation (as well as workflow the items and so on).

The mime type for XHTML already existed in the installation, so I didn't need the instructions here:
http://wiki.alfresco.com/wiki/Adding_a_Mime_Type

But I did have to add the "XHTML" option to the dropdown list in the New Content Rule wizard, so I followed the instructions here:
http://www.alfresco.org/mediawiki/index.php/Web_Client_Configuration_Guide#Transformation_Mimetype

So far, so good, but I'm getting the following exception when I run the transformation:

Please correct the errors below then click Finish.

    * A system error happened during the operation: Transaction didn't commit: Zero scoring transformation attempted: reader: ContentAccessor[ contentUrl=store://2006/3/31/14/8c2964c3-c0fe-11da-b04b-6b5ed75ec74d.bin, mimetype=text/html, size=2694, encoding=UTF-8] writer: ContentAccessor[ contentUrl=store://2006/3/31/14/8c6b01a5-c0fe-11da-b04b-6b5ed75ec74d.bin, mimetype=application/xhtml+xml, size=0, encoding=UTF-8]‍‍‍

I don't know what  "zero scoring transformation" is; I thought that the entry at the bottom of the "RuntimeExecutableContentTransformer" I configured for "tidy" would enter this in the Content Transformation Registry? Is that what is wrong? What scores a transformation?

[joncard]

I opened up the source code and found the exception. It seems either the checkCommand wasn't successful, or the explicitTransformations collection didn't contain the requested transformation. The declaration of the explicitTransformations collection does have the transformation and the logger would have been notified if the collection were empty; I see no such message in the log. (I'll have to double-check whether the log is configured to receive WARN statements from this class.) I have removed the checkCommand and it still doesn't work. I have deliberately sabotaged the checkCommand and it behaves the same. Is there any way to get greater visibility into this without adding log statements and recompiling?