[rules-users] Cannot retrieve an existing WorkingMemory from RuleBase

Hi, I have a method in my code that creates a RuleBase, then adds a new WorkingMemory. I then put that that RuleBase into a Hashtable for later use. Another method receives a Fact along with a reference for an associated rulebase. One these are received, I get the rulebase from the hashtable, then use Set iterator to retrieve the working memory i originally created. At this point I would assert the fact into the retrieved WorkingMemory. However, i get a null pointer, that is, there is no WorkingMemory inside (returned by the Iterator) the RuleBase any longer. Any ideas what is going on? What is even more strange, when I step through the code in debug mode (MyEclipse), it works fine. Just doesn't work at normal runtime. Thanks, Alan J