I have a evil patch that once opened, appears to kill the live.tab object;
I've done some testing and found that if you have about 500 live.tab objects in a patch, new instances stop working. If you take the total down to around 400, new ones start working again.
Here's a patch to demonstrate.
I've tried on two macbook pros, one running the latest lion and the other the latest snow lep;
both running the latest max 6.0.3
do you see what i see?