STEP A )
Please make sure you have installed Remote agent on the virtual server

And make sure  in selection list you selected the server by machine name (virtual machine )
 ( not from your DELL 2003 --> drive name --where virtual os is present)

STEP B)

This occurs when the Volume Shadow Copy Services cannot communicate with VHD mount drivers during the snapshot process causing  the error above to be generated.

Confirm whether VHD mount drivers are installed if this is an initial setup of Virtual Server backup. If VHD mount is already installed, try reinstalling it per the following steps to potentially resolve the backup failure:

How to reinstall the VHD mount drivers

1. Go to Start | Settings | Control Panel | Add and Remove Program.

2. Locate the Microsoft Virtual Server 2005 in the list installed programs.

3. Highlight the Virtual Server 2005 and click Change.  This will open a screen for Custom Setup Changes

4. Click NEXT

5. At the next prompt, select the Custom option and click Next.
6. Deselect the option for VHD Mount

7. Click Install at the next prompt. This will uninstall the VHD mount drivers.

8. Reboot the server.

9. Perform steps 1 thru 4 again, select the VHD mount drivers, and re-install the VHD mount components.

10. Run a backup of Virtual Machine to test.

Note: If the problem persists after the reinstall, then please contact Microsoft to ensure VHD images can be manually mounted using VHD mount commands.

Error message when you back up a Windows Server 2003-based virtual machine on a Windows Server 2008 Hyper-V-based computer: "GetWriterStatus FAILED for Selected writer [Microsoft Hyper-V VSS Writer], writer is in state [9] [VSS_WS_FAILED_AT_FREEZE]"
 http://support.microsoft.com/kb/959978

For more information about VHD mount commands please refer to the following Microsoft Article.
 http://technet.microsoft.com/en-us/library/cc708295.aspx

most of TNotes seem to be more related to win 2008:

http://support.veritas.com/docs/294684   

http://support.veritas.com/docs/312360

thanks to reply

is it the problem because i'm using IBM storage through iSCSI. so the dell 2003 cannot communicate with the storage?

if i ran the "vssadmin list writers"
1)  in Dell Server (Win server03 standard)
      Writer name: "Microsoft Virtual Server 2003 Writer"
      State: [8] Failed
      Last error: Retryable error

2) in Virtual Server 2005 (Win server03 standard)
     Writer name: 'Microsoft Exchange Writer'
     State: [7] Failed
     Last error: Retryable error

 
That might be a prob.  (but a very rare chance of it.)
Try Step A & B
That should help.