For XML parsers you might consider the following:
James Clark's XT- widely regarded.
Microsoft's parser which is now built into the Internet Explorer 5.0
DataChannel's version of the above.
The last three are all java based; all are free. While each comes with
some instructions for use, none could be called transparent in its use.
We use an earlier version of the MS parser which works ok- it's error
reporting is limited to a short notation of the problem and the line
location of its occurance
Head of Processing
Minnesota Historical Society
345 Kellogg Blvd West
St. Paul MN 55102-1906