WD MyBookWorld II freezes every 100MB or so during file transfer

HI

Whenever I transfer movie files greater than 1GB from my laptop to WD, the drive hangs every now and then, and it would take very long to transfer. I will not even be able to access web interface when the drive hangs. As I remember, it was working well before, and this is a recent problem. Any idea what might be causing this issue.

Thanks in Advance.