Java HotSpot Virtual Machine

I have 2 methods I expose in my C++ DLL to my VB app:

1. init_JVM( ) which I want to return a JNIEnv reference. This method is called once from my VB app.
2. convert_Image( ) which passes the JNIEnv object as a parameter back to the C++ DLL. This method is called many times from VB.

So, essentially, my VB code I have:

Declare Function init_JVM Lib "convert.dll" () As Object
Declare Sub convert_Image Lib "convert.dll" (ByRef lpJNIEnv As Any, ByVal strTiffSourcePath As String, ByVal strError As String)

Sub Main( )
  Dim oEnv As Object

  '*** Initialization - create JVM
  Set oEnv = init_JVM()

  For iNum = 0 to nCount
    convert_Image(oEnv)
  Next
End Sub


This is what my C++ looks like:

extern "C" JNIEXPORT JNIEnv *JNICALL init_JVM()
{
  JNIEnv *env;

  // code that creates JVM...

  return env;
}

extern "C" JNIEXPORT void JNICALL convert_Image(JNIEnv *env)
{
  jclass convertClass;

  // BLOWS UP ON THIS CALL
  convertClass = env->FindClass("TConvert");

  // the rest of the code
}

So, TConvert, is a java class. It blows up with an "Unhandled exception" error the first time it hits that line. Everything used to worked well if I didn't pass the env (when everything was in 1 method). But I had to split into 2 methods so that in my VB, I want to be able to only create the JVM once and then call the convert_Image as many times as I need to.

Please help. I think this is just a matter of being able to pass the JNIEnv correctly. What should the object types be in the declare statements in VB?

Thanks in advance.

Ya-Tin