Unfortunately there is a problem currently with Safari, sometimes Animatron crashes it. We could not figure out what is the problem so far, but we are still looking.
It started with recent Safari updates and affect some portion of our users. As soon as we find what the problem is we will immediately release the fix.
BTW Google Chrome works just fine with Animatron, in fact it's faster and much more stable. So if you don't have any particular preferences I would recommend using Chrome.