Sampling using the Structure plugin

[The Acid RAbbit]

Ok, I'm working on a song, and I had a few samples at the beginning that sounded really good, and they were in the perfect spots. I sequenced everything out, and I saved it all properly last time I was working on the file.
However, I've now opened it again to continue working, and the samples are still there and the notes are sequenced out, yet Structure won't create any sound. At all. Yet, when I open structure up, it will still preview the samples for me just fine. But it won't play them during playback, and it won't play them when I press the proper note on my keyboard.

Someone help me out, I've had this problem with Structure before, and the only way I found to solve it was to delete the track and start over. I don't want to have to do that this time.