https://trac.macports.org/wiki/FAQ#selfupdatefails
If your connection to the rsync server fails you may get blocked by a firewall or other network control software. In the new system of Mac, you can stop the service as the image. This new security feature is called GateKeeper. It will also stop you for install other software.
From:http://osxdaily.com/2012/07/27/app-cant-be-opened-because-it-is-from-an-unidentified-developer/
You can use the same method to install your new software. Also just right click the install files and choose open. There will be a window asking you "Are you sure ?". Just answer YES!
Fix the “App can’t be opened because it is from an unidentified developer” Error in Mac OS X
Jul 27, 2012 - 33 Comments