If you are having trouble with the download assistant you can try going without it by downloading thru the site linked below. In case there is some misunderstanding, you do not have to install anything more than the trial version. You use your serial number from the purchase to convert the trial to full usage.
Be sure to follow the steps outlined in the Note: Very Important Instructions section on the download pages at this site and have cookies enabled in your browser or else the download will not work properly.
Photoshop/Premiere Elements 12: http://prodesigntools.com/photoshop-elements-12-direct-download-links-premiere.html
