It may be that you have not purchased or activated the MP4 codec, or it may just be a problem with the the Android OS. Movie Edit Pro version 14 is definitely not compatible with the Android OS and since you did not say if you are importing these files to a Windows computer or if so what the specs for that computer are, It is a little difficult to speculate on what the problem may be. Movie Edit Pro version 14 is windows XP compatible. If you mean Movie Edit Pro 2014, that is different. MEP 2014 is compatible with Windows XP | Vista | 7 | 8 (32-bit and 64-bit) but still not with Android.
So what exactly are your trying to do. Please be much more specific as the product is not designed to run (as far as I know) on your Android device. If you are just trying to import files into a Windows PC, what are your Pc specs and OS version and exactly which version of Movie Edit Pro are you using?
I read perfectly mp4 file from Samsung tablet using MEP version 17 plus probably your version 14 cannot handle or you lack a codec.
My file is 1280 x 720 high definition (light) and transfered to computer using a USB key alsi I can transfer using WiFi and a wireless network using Fuse a special Camtasia Studio apps.
The best way to link the Samsung tablet to a computer you use the USB cable coming with the power supply, wait for detection (Power On the tablet before) Use the copy and paste function. To play the mp4 try the QuickTime player from Apple (is Free) or Windows Media Player last version from Microsoft website.