ILE C++ and ILE RPG

Hello,

Im having a problem with a C++ class that invokes a ILE RPG procedure that is in a service program.
To make it more clear i will write an example here

class Myclass
{

void MethodThatInvokeRpg()
{
RPGPROCEDURE(input);
}

void AnotherFunction()
{
do_some_processing();
}

void FunctionThatInvokesBoth()
{
RPGPROCEDURE(input);
do_some_processing();//here i get a MCH3601 ( null pointer exception )
}


}

int main()
{
Myclass myclass = new Myclass();

myclass->FunctionThatInvokesBoth();

}

After i return from the RPG procedure i can not access the next function due to null pointer exception.
the module invoking the next function is QC2PFMO from procedure _C PSX dofmto, i think is a system prodecure

Thanks for the help