vortex mini media player?

It's a piece of hardware, not a software based media player.

Try playing your video from your USB device or whatever support you are using on your, or another, computer. Skip toward the end and see if you can play them to the end.
The problem may be that the film did not get copied completely to your storage device.
If the file is not complete or is truncated, then it just can't play completely.

If you are using an external hard drive, it's very important to make sure that the files copied are effectively writen to the disk and no longer held in the drive bufer.
One way is to save a scratch file of abour 8 Mb mefore you procede to safely disconnect the unit. Always use the "safe disconnect" even after using a scratch file.

Electro
August 2011