UNRARX

I recently just bought the imac core duo and i have been using unrarx to extract rar files which is not a universal binary and it worked ok. This was until this morninig after i installed the latest security updates. I had no trouble with the inital updates that people are experiencing e.g compuer does not boot up, all went without a hitch. I then tried to extract some rar files i have and the computer just freezes now when i open them up. Any ideas anyone to why i was ok before the latest updates and now with them the computer freezes up when i try and unrar files.