Hmm. The only thing that springs to mind is to check your track lists for any unusual characters, firstly for command characters that might destroy a call, like {}[]@#%:| and the like. Next, and less likely is looking for accented characters, foreign (non-English) characters and so forth. I know the script does some text washing (can't remember the technical term off the top of my head), but you may have run into an exception.