>>>>> "a_stephm" <stephm@...>:

> I have tried trang, with no better out come, and the rnc looks ok to
> me -- though I am no expert. What should I look for, and do you know
> of a way of getting -- say -- line numbers for the error?

I don't know, and it's impossible to say from the description. Perhaps
you should ask on rng-users, perhaps with a posting of the actual schema
file as an attachment?
http://tech.groups.yahoo.com/group/rng-users/

Perhaps ask first if it's ok to send the schema as an attachment? I
don't know what the list's attachment policy is..

> Haven't tried anything libxml2-based. Any suggestions

xmllint: http://xmlsoft.org/xmllint.html

It's a part of libxml2, and usually installed with it. It doesn't do
schema validation, so you will have to try validating a sample document,
and see if you get any schema errors.