Ntfs log error

I am getting the following error in my logs:

The file system structure on the disk is corrupt and unusable. Please run the chkdsk utility on the volume \Device\HarddiskVolume2.

I am not completely certain which volume the error is referring to. Here is the output from diskpart:

DISKPART> list disk

  Disk ###  Status      Size     Free     Dyn  Gpt
  --------  ----------  -------  -------  ---  ---
  Disk 0    Online       931 GB      0 B
  Disk 1    Online       932 GB      0 B
  Disk 2    Online       932 GB    17 MB
  Disk 3    Online       932 GB      0 B

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     E                       DVD-ROM         0 B  No Media
  Volume 1     C                NTFS   Partition    159 GB  Healthy    System
  Volume 2     D                NTFS   Partition    771 GB  Healthy
  Volume 3     X   BACKUP01     NTFS   Partition    932 GB  Healthy
  Volume 4         SBS_Backup   NTFS   Partition    931 GB  Healthy
  Volume 5     F   Monthly Arc  NTFS   Partition    932 GB  Healthy

Physically Volumes C: and D: are partitions on the internal 3 drive RAID 5 array.
Drive X is an external USB drive which is used by the SBS backup exclusively
Drive E is an External USB used for flat file backup
Drive F is an External USB used for archive purposes.

The internal SBS backup has failed the last few days giving a drive related error but the diskpart output makes it look to me like the log entry is referring to  the D: partion (where all our data is). We have not noted any problems accessing or writing to files on the server.

So my question is which drive/partition is the error referring to and how do I go about fixing it. Also what are the risks associated with  running chkdsk on a RAID and are there precautions I should take. Thanks

This stuff scares the crap out of me.........