What are you downloading - a tryout of Premiere Elements 13 or something else?
If you are trying to install purchased or tryout Premiere Elements 13 on a Windows Vista computer with or without SP, be advised that Premiere Elements 13 does not support Windows XP, Windows Vista, or Mac OSX 10.7. No workaround except to use a version of Premiere Elements earlier than 13 or seek another brand video editor.
Please let us know if any of the above applies to you. We will be watching for the details in your reply to decide what next.