I was having this problem before on a USB drive, but now it's happening on my main RAID5-backed hard disk:

2013-10-17 9:37 C:\>dir "C:\Shares\Shared\Reference\Safety Management System\Vid
eo CD\AutoPlay\Docs\Manuel*"
 Volume in drive C has no label.
 Volume Serial Number is 3C18-E114

 Directory of C:\Shares\Shared\Reference\Safety Management System\Video CD\AutoP
lay\Docs

2003-09-09  11:29 PM         1,056,768 Manuel d'intervention d'urgence MFC.doc
2004-06-20  10:36 PM           139,849 Manuel d'intervention d'urgence MFC.pdf
               2 File(s)      1,196,617 bytes
               0 Dir(s)  196,068,691,968 bytes free

2013-10-17 9:38 C:\>dir "C:\Shares\Shared\Reference\Safety Management System\Vid
eo CD\AutoPlay\Docs\Manuel d'intervention d'urgence MFC.doc"
 Volume in drive C has no label.
 Volume Serial Number is 3C18-E114

 Directory of C:\Shares\Shared\Reference\Safety Management System\Video CD\AutoP
lay\Docs

File Not Found

2013-10-17 9:38 C:\>

This is from a Command Prompt window where I went to Properties and told it I wanted to modify who it ran as. I opened it, had it run as me with the "restricted access" unchecked, then ran the above.

The file in question has the following ACLs: Administrators, SYSTEM, and OurCompanyUsers. All three have full control of everything. Nobody has any Deny bits set. I am a member of Administrators. So I don't believe it's a permissions issue.

It's not a USB drive, so this time there is no question of USB hardware.

Windows Server 2003 Standard Edition SP2.

What does this mean? Is this more likely a hardware or software problem?