SQL Server - Creating Folder and Backup Database in Network.

Hi,
  I am trying to write a script in SQL Server 2008 Express Edition for creating a folder in a network drive and then Backup database in that folder. I have tried using the following


DECLARE @DBFolderName sysname
DECLARE @DirPath nvarchar(500)
DECLARE @DirTree TABLE (subdirectory nvarchar(255), depth INT)

-- 2 - Initialize variables
SET @DBFolderName = 'XXX'
SET @DirPath = N'\\ipl20\D\Abcd\' + @DBFolderName

-- 3 - @DataPath values
INSERT INTO @DirTree(subdirectory, depth)
EXEC master.sys.xp_dirtree @DirPath

-- 4 - Create the @DataPath directory
IF NOT EXISTS (SELECT 1 FROM @DirTree WHERE subdirectory = @DBFolderName)
EXEC master.dbo.xp_create_subdir @DirPath

BACKUP DATABASE XXX
TO DISK = @DirPath
WITH INIT,SKIP


While trying to create the above folder a following error appears

xp_create_subdir() returned error 161, 'The specified path is invalid.'

Please do suggest me how to do the same.

Check whether 1st statment creating folder or not, if not try this script to create folder  using  SQL Server sys.xp_create_subdir extended stored procedure.
EXEC master.sys.xp_create_subdir 'C:\SQLDatabases\Test\'

I am able to create a directory using the above command in a local drive but in network I am unable to do so. Returning the same result xp_create_subdir() returned error 161, 'The specified path is invalid.'

The Built-in-account is set to Network Services in SQL Server.