FCP, soundtrackpro and 5.1 ssound

ok here is my problem.

I have an apple pro res 4:2:2 with 5.1 audio in FCP.

I select the audio region, right click and send them to soundtrack pro as audio region.

In soundtrack pro I select all the chanels open them in the edit window, aplly some time stretch and click ok!

Then soundtrack pro tell me: The rendered files can´t be written..?

Scratch disk and such are set right!

Do anybody know something about this problem??

Thank you everybody for your help!!!

/jo