The cause of some 90XX Errors in Pro Tools can be related to bad hard disk performance regardless of the what the Pro Tools Disk Meter is telling you.

This can be caused by not having AHCI enabled in your motherboards BIOS setting or not having the required drivers /software installed in windows.

As i mentioned in the Video, heres a link to a Youtube Video that shows you how to prepare your system before enabling AHCI in your BIOS if Windows was installed before AHCI was enabled.

http://www.youtube.com/watch?v=zRlpE9Ar3v8

*IMPORTANT*

Make sure you create a Windows Backup before making these changes,

Then you can always get back to how your system currently is, if something happens to go wrong.

Neil