There are some issues when debugging Schematron files. Since the first steps are simply
to create an XSLT file, as long as the input XML is well formed it is not likely that
many errors will be found. It is when the generated XSLT file is run against the input
file that the XSLT engine will find the errors. The stylesheet causing the errors
is generated, so the line numbers will not be relevant. You need to trace back from
that stylesheet to the patterns that generated the XSLT to see where the real problem
lies. Not really a problem, just be aware of it.
When using includes or abstract patterns, the errors could well be in the included
files, and the errors won't relate to those files. Again, just use a little logic
to trace the error back to source