You need two install 2 plug-ins in RAD:
- Eclipse Memory Analyzer Plug-in: http://www.eclipse.org/mat/
- IBM Diagnostic Tool Framework for Java Plug-in: http://www.ibm.com/developerworks/java/jdk/tools/dtfj.html#download
This should allow you to read WCS dump files (*.phd). Install #1 then #2.
After that you can follow this tutorial to get ideas on what to investigate: