I know for sure you didn't update plug-ins, because Kontakt 2 is in no way compatible with Pro Tools 8. You need a minimum of 3.5, though 4.0.2 (or higher) is best.
Most likely you have other incompatible plug-ins installed, which will definitely cause crashes and other bad behavior. You should visit our
Plug-In Compatibility Grid and remove or update any incompatible versions (use the right-most column for minimum version info..).