As I also explained in this thread, Premiere Elements does not play well with MP4s from pocket camcorders and smart phones.
Though this might be compounded by your system's resources, if you have less than a quad core or i7 processor.
Thank you Steve for your prompt help.
My processor is Intel(R) Core (TM) 2 duo CPU T8100 @ 2.1ghz.
So presumably until APE catches up I had better continue using my JVC camcorder.
>until APE catches up
The program can't "catch up" since the problem is your hardware is not strong enough to easily edit such a highly compressed, CPU intensive codec
This information is mostly about Premiere Pro, but the requirements are commone
This message has a really good graphic about requirements
CS5 Requirements http://forums.adobe.com/thread/810750
About Requirements http://forums.adobe.com/thread/618058
Disk Configurations http://forums.adobe.com/thread/878419
Some ideas for a Desktop Video Editing PC
-ADK Kudos http://forums.adobe.com/thread/877201
-more build ideas http://ppbm6.com/Planning.html
-Build it Yourself http://forums.adobe.com/thread/815798
I had better start saving up.