Hi, d! Welcome to Muvipix!
You should definitely have the latest version of Quicktime installed on your computer anyway. That's part of the system requirements.
But MOVs, as you say, can be made up of any of hundreds of codecs. It's possible you've got a codec in that file that Premiere Elements can't work with.
As we say in our Muvipix.com Guides, often the easiest solution is to use the program Super to convert it the video to a DV-AVI.
http://www.erightsoft.com/SUPER.htmlTo use Super, set the Output Container drop-down menu to DV -- and leave everything else at its default setting. (Although, if you are using PAL video, ensure that Video Scale Size is set to 720:576.) Drag the video you want to convert to the area just below the Output specs and click Encode.
If you don't mind spending $29, Quicktime Pro does an even better job of converting the video -- and it can even do some basic editing of Quicktime files. It's really a very good investment!