Resolution:
Viewing of instrumentation data from the Admin GUI throws an exception on the web page if the Manager is run using JDK 1.6.

This is due to an incompatibility with the version of Xalan included Java 1.6. The most likely cause is Java 1.6's new bytecode verifier not behaving well with the bytecode generated by the Xalan's XSLTC.

The version of Xalan included in Java 1.6 is the same as Java 1.5, Xalan 2.6.0 which was released in 2004. The latest release of Xalan, 2.7.1, does not exhibit this behavior