Ardour hangs on export.

[guitarman]

Lately I've been having an issue with ardour when I export my session to a .wav file. I select the bus for the export track and set the sample rate to 44100 and set it to be dithered with shaped noise. When I hit the export button the progress bar gets almost to the end looks like about 99% then it just hangs and nothing happens.Ive tried exporting without dithering and using the same sample rate as the recording but it still hangs. The wav file from the export still appears but it cant be played (probly missing something since ardour cant finish the export) but if I convert it to an mp3 with sox the whole song plays through. Not sure whats going on.