Media from Mac problems

Hi,

I have a Mac running snow leopard. When I transfer video media onto my external hard drive, then connect the HD to my WD media player the video’s do not work. it says “unsupported media”. However when I transfer the same video from a PC running Windows 7, the WD media player runs the video perfectly!!??!! Does anyone know why or how I can fix this problem?

Thanks 

Maxw9

What is your external HD formatted to?

NTFS. I have however have special software on my mac (paragon NTFS)  to use a NTFS formatted hard drive normally.