Audio is no longer coming through, any suggestions?

[Ryan ONeal]

hi i'm new to the board..

i'm using the new leopard pre-release LE and here's my problems:

i've opened several of my sessions and some of them will play audio for a little while and suddenly STOP playing back audio.. while the playhead keeps moving.. and after than, it no longer plays any audio.. i can still see the wave files and the curser moving over them.. but no audio through my headphones.

here's my system: mbox mini, mac book pro 15" running leopard 10.5.3, pro tools LE 7.4.2pr

any suggestions? anyone else having this issue? i'm wondering if it has to do with my midi keyboard set up.. playing through the KORG m1? not sure..

thanks!

truly, ryan