cubase 5 (mac) crash sample editor (pitch and warp)

HI all, i have been a cubase user for many years, i have recently moved to a mac, i am running the latest available update for 5, i am in the middle of a big project and almost everytime without fail as i am in the middle of editing vocals in the sample editor in pitch and warp as i try to warp and shorten or lengthen notes it crashes, when i use to run pc till about 2 months ago this never happened, it worked and almost never crashed
im on a macbook pro only 1 month old, osx running 10.6.6, M-audio Ozonic running the 10.66 compatible drivers 64bit.

Model Name: MacBook Pro
Model Identifier: MacBookPro8,3
Processor Name: Intel Core i7
Processor Speed: 2.2 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 8 GB
Boot ROM Version: MBP81.0047.B04
SMC Version (system): 1.70f3

i hope someone might know what to do? is it a driver issue? if i update to cubase six will this issue continue?
thanks very much for any feedback i get, i am in need of help in order to finish this big project i got at the moment