Resolution:
The Decision Manager tester throws an exception similar to the following, reporting that the virtual rule function is not implemented and cannot be invoked even though a Decision Table has been created successfully.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

2010-02-02 11:27:11,734 ERROR DecisionManager.$error     - [BusinessEvents Archive] Got runtime exception while executing Rule be.gen.Theories.BEdestfin.Brules.Brulesets.PrimaryRuleSet.InvokeVRF(Theories.BEdestfin.Brules.Brulesets.PrimaryRuleSet.InvokeVRF) Action be.gen.Theories.BEdestfin.Brules.Brulesets.PrimaryRuleSet.InvokeVRF$InvokeVRF_a@4e0456 Objects &ltbe.gen.Theories.BEdestfin.Bconcepts.SwftInst@id=4>
com.tibco.cep.util.UnimplementedVirtualRuleFunctionException: /Theories/BEdestfin/Brules/Brulefuncs/VRuleFunction is an unimplemented virtual rule function and cannot be invoked until implemented
    at be.gen.Theories.BEdestfin.Brules.Brulefuncs.voidVRuleFunction$002fTheories$002fBEdestfin$002fBconcepts$002fSwftInst$.VRuleFunction(voidVRuleFunction$002fTheories$002fBEdestfin$002fBconcepts$002fSwftInst$.java:7)
    at be.gen.Theories.BEdestfin.Brules.Brulesets.PrimaryRuleSet.InvokeVRF$InvokeVRF_a.execute(InvokeVRF.java:25)
    at com.tibco.cep.kernel.core.rete.ReteWM.resolveConflict(ReteWM.java:252)

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

This happens only when starting the tester in the following way:

1). Deploy tables
2). Commit
3). Approve
4). Start the Tester.

This works without error with BE 3.0.1.

Cause:
======

In BE 3.0.0, if you do a commit after deploy,  these classes will be removed and the tester can not find these classes. An exception is thrown stating that the virtual rule function is not implemented.

Resolution:
=========
Always do a "Deploy Tables" before starting the tester in Decision Manager.