JNI: EndObjGroup for PopLocalFrame Problem

I am trying to use the JNI Push & PopLocalFrame functions to handle my java 
cleanup for groups of objects created in my RPG.  I am using the code provided 
at the following link:
http://faq.midrange.com/data/cache/282.html

My problem is after each time EndObjGroup is executed, it ends the JVM.  From 
my understanding, it's only supposed to remove all the java object references 
within the JVM that were created from RPG since the prior BeginObjGroup 
(PushLocalFrame). But I want to continue using the JVM for other group of 
objects.

Here is my joblog message:
The Java Virtual Machine has ended.                            
Application error.  MCH74A5 unmonitored by QJVAJNI at statement
  0000002581, instruction X'0000'.   

Here is my section of code:
C                   CALLP     beginObjGroup (env : 10000)       
        *  all java in this section works fine.         
                . . .
C                   CALLP     endObjGroup (env)                 
                                                                
   *  this next line creates the error, the jvm has now ended somehow.
C                   CALLP     beginObjGroup (env : 10000)       
C                   EVAL      j_StringObj = j_StringCtor(field1)
C                   EVAL      field2 = jgetBytesMth(j_StringObj)
C                   CALLP     endObjGroup (env)    


Anyone ideas?
Thanks