Hi. Welcome to the board. Unfortunately, format errors on Action chipsets are commonly caused by hacked memory. Scammers hack the players to show more memory than there actually is. It appears to download all your files and you can see them on your player, but when you try to play them you get format errors. This is because a ghost file is written to the player. Follow the instructions posted here:
How To: Removing a Memory Hack.
Also, have a look here:
Petition: Stop the Multi-Million Dollar Fraud