Looks o.k. so far but I can't see any servo objects being created or attached or what's in the pointServoDevice array or quite a lot of other things. I'm assuming it's not going to be anything daft that I might do like falling off the end of one of your many arrays.
Just for interest, if immediately after the failing write, you add a really basic XXX.write(some fixed number) where XXX is point7's basic servo object (i.e. what pointServoDevice[7] points to), what happens then?
Steve