This isn't stopping PHPStorm from working, but I'm seeing this error quite a lot and I wanted to let you know. I'm using PHPStorm 6.0.3 129.757, on OSX 10.9 Developer preview. Every so often I get this error, it might be every time an external task runs. I see it when I run git commands and also it looks like the code sniffer triggered it as well. It happens in RubyMine, too.
I've attached a screenshot with the error message. This doesn't stop the IDE, and in fact the commands complete successfully, but it is accompanied by a "PHPStorm has quit unexpectedly" message from OSX. It's rather amusing, really.
Attachment(s):Screen Shot 2013-06-18 at 11.50.14 AM.png