I think the problem is in the TraxTransformer that no longer supports the "transformer-factory" config option (the Cocoon 2.1.11 version does).In the stx block the stx transformer is declared like this:
so it is using the "transformer-factory" config option. So what happens is, I think, the default transformer factory for XSLT stylesheets is used, it generates a transformer, which is a XSLT transformer, which checks for the version attribute on the <xsl:stylesheet/> element, which does not exist in the STX stylesheet, and it generates the above error. Or something like that.
So, do you have any tips on how to get this working again?