Listing 1: Ailing Query That Won't Run In SQL Server 2000 SP3

EXEC UpdateControlCounter 6326054, 1, { ts '2005-04-15 12:00:00' }, 
      '0001', { ts '2005-07-21 14:46:07' }
EXEC UpdateControlCounter 6326056, 1, { ts '2005-04-17 12:00:00' }, 
      '0001', { ts '2005-07-21 14:46:07' }  
EXEC UpdateControlCounter 6326058, 1, { ts '2005-04-16 10:28:00' }, 
      '0001', { ts '2005-07-21 14:46:07' }  
…
WHERE UpdateControlCounter IS:

CREATE PROCEDURE [dbo].[UpdateControlCounter]
            @RefNo DECIMAL(19),
            @CurrentPPCC INT,
            @LastEffDate DATETIME,
            @LastRefSeq VARCHAR(4),
            @ExportDttm DATETIME
AS
            IF @LastEffDate IS NULL 
                        SET @LastEffDate = '1899-12-31'
            UPDATE ControlCounter
            SET CurrentPPC = @CurrentPPCC, LastEffDate = @LastEffDate, LastRefSeq = 
@LastRefSeq, 
                        ExportedOn = @ExportDttm
            WHERE RefNo = @RefNo