It seems to me that your player has HACKED memory so that when the player reads a certain area of the memory chip (which is hacked), it freezes up.
Try FORMATTING your player and then see if that helps.
Try following the steps here to remove the memory hack:
*
How To: Removing Memory Hack
* or here:
[HOWTO] Remove DISK ERROR! / Error format etc.. on AK2025
Can you give us more details on the player you have? Who you bought it from, URL link etc...?
Also, you can try using
viDrop to convert your videos instead to see if that also helps.
Let us know how you get on.