The .mov format is not a single format, per se, but is actually a package that can be made up of any of hundreds of possible codecs (compression systems), not all of which are supported by Premiere Elements.
Very few smart phone video formats are editable in Premiere Elements. This is likely one of them.
The best solution is to buy Quicktime Pro ($29 from Apple). Not only does the program convert most MOV files to editable DV-AVI videos, but it also includes a number of basic editing features.
thanks for the response. I appreciate what you've said about the .mov format and codecs but what was confusing me was why some were working while others weren't and yet they were all identical. The fact that some play and are importable suggests that it is compatible but doesn't explain why some were described as incompatible. I've now solved the problem by simply closing elements, restarting my PC and all of a sudden all the video files are available. Therefore I can only conclude some sort of bug but thanks for your suggestion anyway.
The bottom line for anybody else who lands here lookoing for an answer to the same problem, try restarting elements or maybe restarting your PC and then see if all your iPhone clips are available. Mine suddenly were which I don't understand but the fact that it's working now will do for me!
Glad you were able to find a workable solution of some sort, Luc!