LinkageError org.xml.sax.Parser

I am deploying my web app to BEA Weblogic Server 10.  My app uses DWR 2.0.1 configured with Spring Framework 2.5.5.  When I deploy my web app, I get the following error:

  java.lang.LinkageError: Class org/xml/sax/Parser violates loader constraints
     at java.lang.ClassLoader.defineClass1(Native Method)
     at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
     at java.lang.ClassLoader.defineClass(ClassLoader.java:465)
     at org.springframework.core.OverridingClassLoader.loadClassForOVerriding(OverridingClassLoader.java:97)
     at org.springframework.core.OverridingClassLoader.loadClass(OverridingClassLoader.java:60)
     ...

  I narrowed the error down by removing all jars from my web app WEB-INF/lib and adding them back one by one, resolving noClassDefFound errors.  Once I added dwr-2.0.1.jar, I received the LinkageError.

Any ideas?  

Thanks,
~Seth