ATA security spec not supported with Maxtor ATA drive

I am using xboxhdm v1.9 and everything went fine, but when I booted linux with locking and unlocking utilities and type lockhd -a it says error: drive does not support ATA security spec. Yet the hard drive is an ATA hard drive, Maxtor 91021U2. So I dont know what the problem is. Any help appreciated.
-Thanks

 

here is a link to a website that explains step by step what to do with pictures to expalain
http://xguides.xbox-scene.com/tikiwiki/tiki-index.php?page=XBOXHDM+for+dummies

 

Ya, I already know how to do everything. Just not sure why it says ATA security spec not supported. Thanks anyway though.