Open your video file in G Spot or Media Info and post to this forum the resolution, frame rate and audio and video codecs that are listed.
Before we can comment, we need to know what that file is made of.
That fact that iMovie is rejecting it is a bit of a red flag. iMovie is compatible with most common video formats and codecs.
What version of Premiere Elements Mac? Nonetheless, it is highly lightly that your device is recording with a variable frame rate instead of a constant one. Premiere Elements does not fare well with that type of frame rate. The Premiere Elements symptoms range from audio out of sync to not being able to import the video at all. The typical remedy is to take that video into a free program HandBrake to obtain the H.264.mp4 with constant frame rate which you then import into Premiere Elements with Expert workspace Add Media/Files and Folders/Project Assets.
You do not confirm this situation with GSpot, rather with MediaInfo for Mac which will confirm the "diagnosis" by showing 3 frame rate under the file's video properties - minimum frame rate, frame rate, maximum frame rate. Just be careful in your downloading and installing choices for MediaInfo since it has been known to travel with unwanted baggage. MediaInfo Mac (Mac) - Download
The HandBrake cure or no cure might serve as variable frame rate confirming if you did not want to go the MediaInfo proof.
Please consider, and then let us know the outcome. Any questions, please do not hesitate to ask. All the properties of the Photobooth video are important and have been asked for already. But, the variable frame rate seems important to point to in order to rule that in or out at the onset since you do write that you can import this Photobooth video into the Premiere Elements project.
seems I had this issue before. Is it possible I uninstalled the program and re-installed to correct it? I'm actually having this problem again......after 10 update.......surprise!!
This thread is nearly a year old and some of its correspondents no longer frequent this forum.
You may want to start a new thread and explain in detail what issue you're dealing with an on which version of the program.