locating the invalid element in a large xml document

Greetings, 

I have a fairly large schema (around 10K lines long) that will be
validating even larger XML documents. 

If the schema validator finds an element which is not valid, it returns
the element name and the error. 

There may be many elements that have the same name who are siblings. 

How can I find out which element in the input data document is the
invalid one? 

Is there a way to include positional information in this error from the
schema validator?  Or maybe generate a unique id for each element in the
input data document and include that id as part of the error. 

Thanks in advance, 

--  

James Neff
Technology Specialist 

Tethys Health Ventures
4 North Park Drive, Suite 203
Hunt Valley, MD  21030 

office:  410.771.0692 x103
cell:    443.865.7874