Make sure you have ASIO4ALL set up properly.
You can watch this
tutorial video from the forums own Benoni on how to do this.
Once ASIO4ALL is properly configured, try holding down the N key while PTF loads, which will force the playback engine to display and allow you to choose your audio device.
If that doesn't work, then like the others said, we will need more specific information about your system and exactly what you are doing when you get the error to be able to offer any kind of help.
Thanks,
Will