What version of Premiere Elements, what computer operating system?
The first question when you mention importing/editing/exporting a file with a .mov file extension is typically "Do you have the latest version of QuickTime 7 installed on your computer along with Premiere Elements?
That is a System Requirement for Premiere Elements.
Depending on your answer to that, then we need to have information on the properties of this .mov file which is giving you the error message when you go to import it into your Premiere Elements project? Telling us the brand/model/settings of the camera that recorded the video may give us the troubleshooting information needed. Did you record this video with a device such as iPhone, iPad, or screen capture program?
Lots more questions depending on the flow of the exchange of information. Let us start here and then decide what next based on the details in your reply.
Any questions or need clarification on the above, please do not hesitate to ask.