Does it happen with every single maxscript or just some specific ones? If so, which specific ones? And are you doing anything specific before you run the script or can you just startup max, make a box, run the script and it'll crash?
undo "Description of whats being done" on(--your code here) everything with parenthesis will be stored in 1 undo event. if this crashes then post code. Or as Perna says 'maxscript help'->'index'->'undo' Perna: do you think you could get your post added as a button to the quick reply dialog? :D