Do you have Stuffit installed? If so, you will probably need to change the default application that opens .bin files.
Select the .bin file, and choose "Get Info" from the File menu. Beneath "Open With", select Stuffit Expander (if it's not listed, you may have to choose "other", and locate it in the Applications or Utilities folder). Then hit "Change All..." if you want to make sure that all .bin files open with Stuffit. Good luck.
Most of the time I download Stuffit just to makes sure I can open these files. If you have more knowledge with Unix/Linux you can decompile those files in the Terminal. But even so the GUI is very easy to use and also easy to trouble shoot.