Dit is dus de foutmelding die ik krijg : org.apache.xerces.jaxp.SAXParserFactoryImpl not found. En nu is de vraag : heb ik nog een Java Archive of JAR-file nodig die me aan die klasse kan helpen ?

Ik vind op http://dev.eclipse.org/newslists/news.eclipse.newcomer/msg20084.html een bericht dat sterk op mijn foutmelding trekt. En ik citeer.
Just updated to Mac OS X 10.5 and suddenly Eclipse (3.3.1.1 Build id: M20071023) ant tasks fail to run, saying:
XML parser factory has not been configured correctly: Provider org.apache.xerces.jaxp.SAXParserFactoryImpl not found
What jar contains org.apache.xerces.jaxp.SAXParserFactoryImpl ? If I find it, where should it go?

En het antwoord hierop is het volgende :

Hi Chris,

Unless you're trying to run a Web Tools ant task I don't think this is WTP 
related. However, the parser in question is from the Apache Xerces [1] 
project. In this context Xerces is a Java based XML parser. You're likely 
getting this error because Xerces is not included in your JRE. (I'm not 
familiar with the Max JRE but this used to happen with older Sun JREs.)

Xerces is available as a bundle from the Orbit project [2] and is 
available in Eclipse (if installed) in the bundle org.apache.xerces. Add 
this bundle or the Xerces jar to your path and you should be good to go.

Lawrence

[1] http://xerces.apache.org/xerces2-j/
[2] http://www.eclipse.org/orbit/