I have noted an issue involving the system midiserver crashing which is possibly what you are seeing here . . .
Can you get them to check console crash logs if they experience it or if you do? Also system setup and any other midi drivers in use is also important info. . . .
I have not had a huge play yet but have not had many issues and have not had to go to those lengths to sort it out, yet . . I have had the SS editor , Live with SScrollr and Max with multiple [ss] all running as mentioned in another post. . i guess mileage varies.
Hope to do a bit more stuff soon . . .
KMI StringPort_1650, SoftStep_VK2 v1.2 & MIDI Expander; Mac_Moore Guitar,
Roland VG 8, 88 & 99, YamahaVL 70m; OSX 10.6.8, iMac i7 2.8G QC; MaxMSP 5.1.8, Ableton Live 8.2.2, M4L, SC3, QC, cSound, etc, etc,