When you try to use NTBackup with Windows Server 2003 it fails stating that the operation did not successfully complete showing error: Error returned while creating the volume shadow copy:0xffffffff. This issue occures when the VSS system files are not registered.

The workaround on this issue is to re-register VSS system files.

Create a batch file with the following:

cd /d %windir%\system32
Net stop vss
Net stop swprv
regsvr32 ole32.dll
regsvr32 oleaut32.dll
regsvr32 vss_ps.dll
vssvc /register
regsvr32 /i swprv.dll
regsvr32 /i eventcls.dll
regsvr32 es.dll
regsvr32 stdprov.dll
regsvr32 vssui.dll
regsvr32 msxml.dll
regsvr32 msxml3.dll
regsvr32 msxml4.dll

Execute the batch file to allow re-registration of vss system files and try to run the ntbackup again.

You can use vssadmin to list writers:

vssadmin list writers