Okay, it could be your Environmental Variables. Make sure it is trying to load java from the correct location. If it is not that then maybe you are trying to do an emote that isn't coded into your server/client. If it is that, then it will crash when you do it, or else mess up and do a weird emote. If it is not either of those, then it could be your java itself crashing which means you would have to update, that would probably be it. If it is actually showing the interface that says the client crashed, then you messed up your cache and need to replace it. Those are all i really know as of right now... I am also tired so i might have missed something.