It can't find the class DocumentImpl in Xerces. Make sure that the
Xerces jar file is in the expected library location, and that the jar
file you have contains com.sun.org.apache.xerces.internal.dom.DocumentImpl .

I got the same problem when i use tomcat & Jdk1.5.

Actual Problem is Jdk1.5 have latest version of parsers,tomcat using older versions parses, if your application using latest version of parser new methods you may got these type of errors.

Solution:

One solution is remove the jar files from Tomcat 5.0\common\endorsed
directory.I think this solution is solve your problem.