I have purchased an IMac and I am trying to download CS6 to it. It is downloading but keeps stalling. I pulled up my downloads and it tells me that "There is no application set to open the document Photoshop_13_LS16.dmg.port."?

that's a partial download.  delete it.

use a different connect (you can transfer to your imac on an usb stick, eg), use a different browser and/or use a download manager.

also,

if you follow all 7 steps you can directly download a trial here:  Download Adobe CS6 Trials: Direct Links (no Assistant or Manager) | ProDesignTools

and activate with your serial number.

if you have a problem starting the download, you didn't follow all 7 steps, or your browser does not accept cookies. 

the most common problem is caused by failing to meticulously follow steps 1,2 and/or 3 (which adds a cookie to your system enabling you to download the correct version from adobe.com). 

failure to obtain that cookie results in an error page being displayed after clicking a link on prodesigntools.com or initiates the download of an incorrect (eg, current) version.