In order for us to help you, we are going to need a lot more information.
What version of Premiere Elements do you have and on what computer operating system is it running?
What are the properties of what you have put on your Timeline for export?
And, how are you exporting
If Premiere Elements earlier than 11, then Share/?
If Premiere Elements 11, the Publish+Share/?
Do you have the latest version of QuickTime installed on the computer with Premiere Elements?
Are you running the program from a User Account with Administrative Privileges?
Let us start here and please try to answer all the questions all at one time so that we can give you the best possible answer based on them.
If you need clarification on anything that I have written, please do not hesitate to ask.
Welcome to the forum.
Once, File>Export was where one looked to output a file. That changed with about PrE 7, when output functions were moved to the Share menu. With PrE 11, that process changed slightly to Publish + Share.
That is why the questions have been asked about your version. Things have changed.