Error in SP to retrieve Month Details

month   year         Date                percentage   Cumulative_percentage

NULL    NULL    NULL                       0             0
6   2011    2011-06-30 23:59:59.000 0.774743366259926   0.774743366259926
7   2011    2011-07-31 23:59:59.000 3.87371683129963    4.64846019755956
8   2011    2011-08-31 23:59:59.000 5.42320356381949    10.071663761379
9   2011    2011-09-30 23:59:59.000 0.774743366259926   10.846407127639
10  2011    2011-10-31 23:59:59.000 13.1706372264187    24.0170443540577
11  2011    2011-11-30 23:59:59.000 4.2610885144296     28.2781328684873
12  2011    2011-12-31 23:59:59.000 9.68429207824908    37.9624249467364
1   2012    2012-01-31 23:59:59.000 6.58531861320937    44.5477435599458
2   2012    2012-02-29 23:59:59.000 19.7559558396281    64.3036993995739
3   2012    2012-03-31 23:59:59.000 4.64846019755956    68.9521595971335
4   2012    2012-04-30 23:59:59.000 8.13480534572923    77.0869649428627
5   2012    2012-05-31 23:59:59.000 0.968429207824908   78.0553941506876
6   2012    2012-06-30 23:59:59.000 11.6211504938989    89.6765446445865
7   2012    2012-07-31 23:59:59.000 2.32423009877978    92.0007747433663
8   2012    2012-08-31 23:59:59.000 6.83711020724385    98.8378849506101
12  2012    2012-12-31 23:59:59.000 1.16211504938989    100

8      2012     2012-08-31       6.83711       98.8378
9      2012     2012-09-30         0           98.8378
10     2012     2012-10-31         0           98.8378
11     2012     2012-11-30         0           98.8378
12     2012     2012-12-31        1.1621       100

ALTER PROCEDURE [dbo].[lntsp_Drawing_Not_Released_Approved_Details]      
(         
 @Trans_Type VARCHAR(15),      
 @Proj_Code VARCHAR(15),      
 @Disc_Code VARCHAR(15)=NULL,      
 @To_Date DATETIME=NULL,      
 @Dwg_Type BIT=NULL,      
 @SE_Code INT=NULL,      
 @SED_Code INT=NULL                                           
)                                                    
AS 
BEGIN      
   DECLARE @Drawing_Schedule TABLE        
 (        
  Doc_Id INT,        
  Doc_No VARCHAR(50),      
  Title VARCHAR(250),       
  Weightage FLOAT,      
  Approval_Date DATETIME,      
  Release_Date DATETIME,      
  Disc_Code VARCHAR(15),        
  Dwg_Category_Code VARCHAR(15),        
  Dwg_Size_Code VARCHAR(15)        
 )      
      
    INSERT INTO @Drawing_Schedule        
  SELECT Doc_Id, Doc_No, Title, Weightage, Approval_Date,       
  Release_Date, Disc_Code, Dwg_Category_Code, Dwg_Size_Code        
  FROM PTS_H_Drawing_Schedule DS        
  WHERE DS.Proj_Code=@Proj_Code      
  AND DS.Approval_Tag='Y'      
 END      
      
   IF @Trans_Type='SCurve'      
   BEGIN      
      
   DECLARE @Total_Weightage_Approval FLOAT        
             
     SELECT @Total_Weightage_Approval=SUM(ISNULL(Weightage, 1))        
     FROM @Drawing_Schedule        
     WHERE Dwg_Category_Code='DWG000002'      
        
           
        
     DECLARE @Planned_For_Approval_Date TABLE        
     (         
      Doc_Id INT,        
      For_Date DATETIME,        
      Weightage FLOAT        
     )        
      
     INSERT INTO @Planned_For_Approval_Date        
     select 0 as Doc_Id, Proj_Start_Date, 0 as Weightage        
     from PTS_H_Projects   where Proj_Code=@Proj_Code        
      
     INSERT INTO @Planned_For_Approval_Date        
     SELECT ISNULL(DR.Doc_Id, DS.Doc_Id),        
     ISNULL(MIN(DR.Approval_Date), MIN(DS.Approval_Date)), ISNULL(Weightage, 1)        
     FROM @Drawing_Schedule DS        
     LEFT OUTER JOIN PTS_T_Drawing_Revision DR        
     ON DS.Doc_Id=DR.Doc_Id --AND DR.SNo=1        
     WHERE Ds.Dwg_Category_Code='DWG000002'      
     GROUP BY DR.Doc_Id, DS.Doc_Id, Weightage        
        
     DECLARE @Planned_For_Approval_Month TABLE        
     (         
      SNo INT IDENTITY(1,1),        
      For_Month INT,        
      For_Year INT,        
      DateC DATETIME ,        
      Weightage FLOAT,        
      Percentage FLOAT        
     )        
              
             
     INSERT INTO @Planned_For_Approval_Month        
     (For_Month, For_Year,DateC, Weightage, Percentage)        
     SELECT MONTH(For_Date) AS For_Month,         
     YEAR(For_Date) AS For_Year,        
     DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,For_Date)+1,0)),        
     SUM(Weightage) AS Weightage,        
     SUM(Weightage*100/@Total_Weightage_Approval) AS Percentage        
     FROM @Planned_For_Approval_Date        
     GROUP BY MONTH(For_Date), YEAR(For_Date) ,DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,For_Date)+1,0))        
     ORDER BY For_Year, For_Month        
        
            
        --PLANNED_FOR_APPROVAL        
        SELECT P2.For_Month, P2.For_Year,P2.DateC, P2.Percentage,         
        SUM(P1.Weightage*100/@Total_Weightage_Approval) AS Cumulative_Percentage        
        FROM  
        @Planned_For_Approval_Month P1        
        JOIN @Planned_For_Approval_Month P2        
        ON P1.SNo <= P2.SNo        
        GROUP BY P2.For_Month, P2.For_Year, P2.Percentage,P2.DateC         
        ORDER BY For_Year, For_Month        
      
            
   END