Problem creating/accesing a document dictionary

I have problems creating and accessing a document dictionary.

I create a new docuemnt using  the NEW item in the Illustrator menu.

Then I execute the following code through my plugin. I does not work. That is I a unable to retrieve any value fro the dictionary . Actually I am not even sure I wrote anything in the  dictionary.

Is there anything wrong in my code ?

thanks.

{    

    AIDictionaryRef dictionary =NULL ;

    AIErr error = 0;

    error= sAIDocument->GetDictionary ( &dictionary );

    AIDictKey KEY = sAIDictionary->Key( "MY_Key" );

    string mykey= "2";

    error = 0;

        error= sAIDictionary->SetStringEntry ( dictionary, KEY , mykey.c_str());

    AIErr error = 0;

    error= sAIDocument->GetDictionary ( &dictionary );

    const char* Namevalue ;

    error = sAIDictionary->GetStringEntry(dictionary, KEY, &Namevalue);   

    sAIDictionary->Release (dictionary);

}