Apple Logic Pro /LogicExpress Discussion

Hello to all,

I have this recurring problem with Logic Pro 8. Volume automation for MIDI tracks become unresponsive, ie. the volume and the mixer fader do  not change even with changing automation data. It has happened to multiple MIDI tracks and so far it has not happened to an Audio track.

I can temporarily get around this issue by going back to an older saved file but eventually the issue comes back.

Here are the things that I've tried to fix this bug:

None of these worked: 
-Changed the MIDI channel.
-Created a new MIDI track with a different MIDI channel.
-Shutdown logic and reopend the file. Projects still had the problem.

These temporarily restored automation functionality:
-Closed the current project and opened an older edit. This was fine for a bit but the same problem arose. This time on a different MIDI track with a different patch assigned to it.
-Shutdown computer and reopened an hour later. Ok for a bit but the problem returned.

I hope somebody has a solution to this issue.
Thanks,
Ben

Logic Pro 8
MacBook os x 10.5.7
M-Audio Audiphile USB