Mainstage Midi Dropouts

I'm building a large system. Only one plugin and the rest is midi routing. The Mac is OS X 10.7.4 and I'm using MS 2.2.2. Through extensive troubleshooting, I've ruled out the external hardware and the midi dropout occur with Mainstage. I did an additional test using Digital Performer 7 and yeilded the same results. DP is only on one computer and not on the other 2 but I am using a MOTU midi express XT as my interface with their most current driver. When I bring up the Mainstage Concert in my 10.6.8 computer, I don't have any problems

The strange part is this; for the past week I have been programming 12-14 hour days and never had a problem what-so-ever. The artist came in to check out the new rig and was very happy. Mainstage was knocking it out of the park. I tore down the rig to build it into its' tour rack and then pull the "A" system back to the area that we will continue to program new patches. At that time, the midi notes were inconsistant and occasionally locked up. Program changes reacted the same. It did it in my 76 patch concert and also in my 2 patch previously saved concert.

Do I have to degrade my new laptops to 10.6.8 to have stability. I'll do what it takes but if there's a fix that I'm missing or something on that should be off, I'll appreciate any clues and solutions. I'm using Mainstage to replace some old sound modules and the MTP USB which still needs system 9 to program and is always buggy. Mainstage has hit a homerun with their midi patching, I just need it to work always. Strange how it was fine for a week until breaking down the system. I could go on....

Thanks!!!!