sql exec copy file failed

[ddtpmyra]

I need help to make this procedure copying file works for me.

The error is
Msg 50000, Level 16, State 1, Procedure sp_copyfile, Line 23
File copy failed

USE [NGProd]
GO
/****** Object:  StoredProcedure [dbo].[copyfile]    Script Date: 12/20/2011 10:37:44 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[copyfile] @sourcefilepath sysname, @targetfilepath sysname=NULL
AS

SET NOCOUNT ON
IF (@sourcefilepath='/?') OR (@targetfilepath IS NULL) GOTO Help

DECLARE @cmdstr varchar(8000)

CREATE TABLE #cmd_result (output varchar(8000))

EXEC master..xp_sprintf @cmdstr OUTPUT, 'copy %s %s',@sourcefilepath, @targetfilepath

INSERT #cmd_result
EXEC master..xp_cmdshell @cmdstr

SELECT * FROM #cmd_result

IF EXISTS(SELECT * FROM #cmd_result WHERE output like '%file(s) copied%') BEGIN
    SET @cmdstr='The file copy operation "'+@cmdstr+'" was successful (at least one file was copied)'
    PRINT @cmdstr
    EXEC master..xp_logevent 60000, @cmdstr, 'INFORMATIONAL'
END ELSE RAISERROR('File copy failed',16,1)

DROP TABLE #cmd_result 
RETURN 0

Help:

print 'Error'