"No More Encoding" Error

I recently bought a yamaha audiogram 6 and got a cubase AI 5 along with it. I have registered it and been using it. Now, I am not able to export tracks in any format. When i export to mp3, it says “no more encodings”. Do i need to buy anything else to export files? In other formats(wav, wma) it exports but the file does not play. When i import them to cubase, it shows no signal.

Thank You,