When run SQL query get long queries running I get error ?

Msg 535, Level 16, State 0, Line 52
The datediff function resulted in an overflow. The number of dateparts separating two date/time instances is too large. Try to use datediff with a less precise datepart.
Msg 16917, Level 16, State 2, Line 54
Cursor is not open.
Msg 16917, Level 16, State 1, Line 104
Cursor is not open.

(0 row(s) affected)

DECLARE	@spid INT ,
	@stmt_start INT ,
	@stmt_end INT ,
	@sql_handle BINARY(20)

DECLARE	@ProcessID INT ,
	@Duration VARCHAR(MAX) ,
	@ProgramName VARCHAR(MAX) ,
	@HostName VARCHAR(MAX) ,
	@LoginName VARCHAR(MAX)

DECLARE	@Processes TABLE
	(
	  ProcessID INT ,
	  Duration VARCHAR(MAX) ,
	  ProgramName VARCHAR(MAX) ,
	  HostName VARCHAR(MAX) ,
	  LoginName VARCHAR(MAX) ,
	  Query VARCHAR(MAX)
	)

DECLARE crsProcesses CURSOR FAST_FORWARD READ_ONLY
FOR
	SELECT	p.spid ,
			RIGHT(CONVERT(VARCHAR, DATEADD(ms,
										   DATEDIFF(ms, P.last_batch,
													GETDATE()), '1900-01-01'), 121),
				  12) AS 'batch_duration' ,
			P.program_name ,
			P.hostname ,
			P.loginame
	FROM	master.dbo.sysprocesses P
	WHERE	P.spid > 50
			AND P.STATUS NOT IN ( 'background', 'sleeping' )
			AND P.cmd NOT IN ( 'AWAITING COMMAND', 'MIRROR HANDLER',
							   'LAZY WRITER', 'CHECKPOINT SLEEP', 'RA MANAGER' )
	ORDER BY batch_duration DESC

OPEN crsProcesses

FETCH NEXT FROM crsProcesses INTO @ProcessID, @Duration, @ProgramName,
	@HostName, @LoginName

WHILE @@FETCH_STATUS = 0
	BEGIN

		SET @spid = @ProcessID

		SELECT TOP 1
				@sql_handle = sql_handle ,
				@stmt_start = CASE stmt_start
								WHEN 0 THEN 0
								ELSE stmt_start / 2
							  END ,
				@stmt_end = CASE stmt_end
							  WHEN -1 THEN -1
							  ELSE stmt_end / 2
							END
		FROM	master.dbo.sysprocesses
		WHERE	spid = @spid
		ORDER BY ecid

		INSERT	INTO @Processes
				( ProcessID ,
				  Duration ,
				  ProgramName ,
				  HostName ,
				  LoginName ,
				  Query
				)
				SELECT	@ProcessID AS ProcessID ,
						@Duration ,
						@ProgramName AS ProgramName ,
						@HostName AS HostName ,
						@LoginName AS LoginName ,
						SUBSTRING(text, COALESCE(NULLIF(@stmt_start, 0), 1),
								  CASE @stmt_end
									WHEN -1 THEN DATALENGTH(text)
									ELSE ( @stmt_end - @stmt_start )
								  END) AS Query
				FROM	::
						fn_get_sql(@sql_handle)



		FETCH NEXT FROM crsProcesses INTO @ProcessID, @Duration, @ProgramName,
			@HostName, @LoginName

	END

CLOSE crsProcesses

DEALLOCATE crsProcesses

SELECT p.ProcessID
		, p.Duration
		, p.ProgramName
		, p.HostName
		, LoginName = MAX(p.LoginName)
		, ThreadCount = COUNT(*)
		, p.Query
FROM	@Processes AS p
GROUP BY p.ProcessID
		, p.Duration
		, p.ProgramName
		, p.HostName
		, p.Query