Mixdown trouble Cubase Elementes 8

Somebody knows what the actual fuck is happening with my cubase? i spend a entire day mixing a new track then when im going to export the final master the export option is not there no more, neither the sample rate and the other options, already reboot my PC and try to export another projects, and the results are the same :neutral_face: :question: :question:

Somebody knows what can i do?