VixMntapi_Init returned error code 6

I am using the latest VDDK ver 5.0 on windows 7 64-bit against ESXi host.

Prior to this call, I called the VixDiskLib_Init which returned successfully.

Here is the code snippet:

vixError=VixDiskLib_Init(VIXDISKLIB_VERSION_MAJOR,

VIXDISKLIB_VERSION_MINOR,

NULL,NULL,NULL,// Log, warn, panic

appGlobals.libdir);

CHECK_AND_THROW(vixError);

   // this succeeded

     // this failed with error code 6

Your help is grealy appreciated

ahalimz