This is a question that has been confusing some people since we launched our first edition of jamproject. The problem with those tracks that stop at middle is not of the program.. it's simply that, like many of the songs we added to our initial pack were still in test, some of them just weren't finish at the time we collected them, and so they're partial unfinished works. For those who want to finish them, please feel free to do so and send us the completed one. You may use EoF or FeedBack for finish those tracks if you want =)
We are very sorry for that Inconvenient! Hope this clears out that doubt!