Thanks for the replies guys. The only concern for the commercial products with 30 day trials is I would want to start using it when I am a little further along and when I will have more time to work on this. In two weeks I get all my teeth removed and will likely be stuck at home for a bit.
For any who were not at the meeting, I am not really looking for a way to edit XML. I am creating XML from C code and when xmllint tells me something does not fit in the pre-existing schema, it is not always easy to learn why.
It was suggested that some editor with extensive support might be able to look/edit the code and knowing the schema(s) involved be able to show me what is needed to fix the xml output from my program.