As John says, you'll definitely need to convert that video to a DV-AVI, per the FAQs to the right of this forum. Prizm is an excellent, free video converter.
MP4 video from flash-based camcorders often use codecs that are incompatible with many video editing programs.
Thanks for the convert suggestion... sorry I'm running this whole thing up again, as you probably recall this coming up last week or so...
Reason is, after doing more research, I get the distinct impression from reviews and comments that have been published that one ought to be able to edit these videos in "the commonly available editors", as it was stated in one review.
That reviewer mentioned Sony Vegas Movie Studio as being one that "just worked with the Samsung out of the box". I downloaded and tried the Vegas product today, and sure enough, without any problem, it very nicely allows one to smoothly work with the Samsung's MP4. Going back to PE7, not the case. I know in the past, earlier versions of Vegas were not at all well rated, but in checking out V9 today, I was fairly impressed at how it looks to be as flexible and capable as PE has been.
So, since we have REALLY enjoyed the PE experience, I was hoping we could find a solution, rather than having to spend lengthy amounts of conversion time for each clip... that just doesn't cut it.
I guess if there's no solution other than pre-conversion, we'll have to go to the Sony software platform, as it appears to function correctly, at least in this case.
Thanks to all for your help and interest.