jsf/Tomahawk - java.lang.ClassCastException: org.apache.xerces.jaxp.SAXParserFactoryImpl incompatible with javax.xml.parsers.SAXParserFactory error

Hello,
I'm encountering a bit of a problem with jsf/tomahawk and hope someone
can point me to the right direction.

In RAD, I've created a new test web project to use jsf and tomahawk to
create a web app. Everything works well.

I then performed that same configuration steps to setup jsf/tomahwak on
the actual (exisitng) web project that I'm supposed to develope my apps
in. When I start the WAS6.1 server, I'm getting the following error in
SystemOut.log:
[6/21/11 9:40:49:332 CDT] 00000016 Digester E
org.apache.commons.digester.Digester getParser Digester.getParser:
java.lang.ClassCastException:
org.apache.xerces.jaxp.SAXParserFactoryImpl incompatible with
javax.xml.parsers.SAXParserFactory


I'm assuming that this is caused by sometype of class conflict between
the existing web app and jsf/tomahawk. My question is does anyone know
how I can find out what jar files is causing this conflict?

Thanks