Hey thanks everyone for all of your help and work on this issue. I've never dealt with change messages before so it took some research to get a basic grasp of the concept. Unfortunately I cannot provide a lot of insight into what worked exactly, but I finally got it working. Basically it required me changing the sound to the desired sound while the MIDI passage was playing in Ableton. Before I had Strings selected and then I pressed play, and the Piano sound was recorded. Now that I changed to the string sound while Ableton was in the process of playing the MIDI passage, the correct sound comes out. Furthermore, it continues to play the proper sound if I stop and start it now.
Thanks everyone for all of your help.