What version of Premiere Elements and on what computer operating system is it running?
Is this a "it worked before but not know" or "it never worked before".
Does the problem exist with the antivirus and firewalls disabled? Do you have the latest version of QuickTime installed? Are you work from a user account with administrative privileges?
Please give the above details so that we can start to customize a reply and avoid asking unnecessary questions. There are always a lot of details to exchange, so best to try to eliminate what is not needed if we can.