Error Message This Record Has Been Allocated Elsewhere

 Hi i get an error whenever i try to insert some data into my database, the error basically says that the record has been inserted elsewhere, this might be from the way my code has been formed, can you see any mistakes in my code below;  1 --This stored procedure allocates serial numbers to a rep.
2 --Allocating by taking the Rep_ID as the search criteria input values as input parameters
3 --and start and end range of serial numbers.
4
5 CREATE PROCEDURE wc_Stock_Allocate_Update @Start_RangeID int, @End_RangeID int, @Rep_ID int, @IsAllocate bit, @ROWCOUNT int out , @TotalRequestedCards int out ,@Product_ID int , @OutputMsg varchar(200) out
6
7 AS
8 --BEGIN TRANSACTION
9
10 DECLARE @Start_Range_ID int
11 DECLARE @End_Range_ID int
12
13 SELECT @Start_Range_ID = Serial_ID FROM tblSerial WHERE Serial_No=@Start_RangeID AND Product_ID=@Product_ID
14 if IsNull(@Start_Range_ID,0)<1
15 begin
16 set @OutputMsg = 'Invalid Start Serial No'
17 return
18 end
19 SELECT @End_Range_ID = Serial_ID FROM tblSerial WHERE Serial_No=@End_RangeID AND Product_ID=@Product_ID
20 if IsNull(@Start_Range_ID,0)<1
21 begin
22 set @OutputMsg = 'Invalid End Serial No'
23 return
24 end
25
26 DECLARE @strSQL varchar(5000)
27 DECLARE @ThereIsCriteria bit
28 --DECLARE @TotalRequestedCards int
29
30 SET @ThereIsCriteria =0
31 --SET @TotalRequestedCards = (@End_RangeID - @Start_RangeID)+1
32 DECLARE @RangeDifference INT
33 DECLARE @TotalAlreadyAllocated int
34 SELECT @RangeDifference = COUNT(*) FROM tblSerial WHERE Serial_ID >=@Start_Range_ID AND Serial_ID <= @End_Range_ID
35 SELECT @TotalAlreadyAllocated = COUNT(*) FROM tblSerial WHERE Serial_No >=@Start_RangeID AND Serial_No <= @End_RangeID AND (isnull(Rep_ID,0)>0)
36 --SET @TotalRequestedCards = @RangeDifference - @TotalAlreadyAllocated
37 --if @IsAllocate=0
38 SET @TotalRequestedCards =@RangeDifference
39 IF @IsAllocate = 1
40 BEGIN
41 SET @strSQL = 'UPDATE tblSerial SET Rep_ID=' + LTRIM(RTRIM(CONVERT(CHAR(10),@Rep_ID))) +
42 ', Allocation_Date=GetDate() WHERE Serial_No BETWEEN ' + LTRIM(RTRIM(CONVERT(CHAR(10), @Start_RangeID ))) + ' AND ' + LTRIM(RTRIM(CONVERT(CHAR(10), @End_RangeID ))) + ' AND (tblSerial.Rep_ID=0 OR tblSerial.Rep_ID IS NULL) AND Product_ID=' + ltrim(rtrim(convert(varchar,@Product_ID)))
43
44 END
45 ELSE
46 BEGIN
47 SET @strSQL = 'UPDATE tblSerial SET Rep_ID=0
48 , Allocation_Date= ' + CHAR(39) + '1/1/1999' + CHAR(39) + ' WHERE Serial_No BETWEEN ' + LTRIM(RTRIM(CONVERT(CHAR(10), @Start_RangeID ))) + ' AND ' + LTRIM(RTRIM(CONVERT(CHAR(10), @End_RangeID ))) + ' AND (tblSerial.Rep_ID='+ ltrim(RTRIM(CONVERT(CHAR(10),@Rep_ID))) + ') AND Product_ID=' + ltrim(rtrim(convert(varchar,@Product_ID)))
49
50
51 END
52
53
54 exec (@strSQL)
55 SET @ROWCOUNT = @@ROWCOUNT
56
57 --Make sure this has saved, if not return 10 as this is unexpected error
58
59 IF @ROWCOUNT<1
60 BEGIN
61 RETURN @@error
62 END
63 ELSE
64
65 BEGIN
66
67 print @Start_RangeID
68 DECLARE @Tstamp timestamp
69 DECLARE @Stock_ID int
70
71 IF @IsAllocate = 1
72 BEGIN
73
74 declare @Stock_IDpass int
75 declare @StockSTatus_IDpass int
76 declare @ToRep_IDpass int
77 declare @Start_Range_IDpass int
78 declare @End_Range_IDpass int
79 declare @Product_IDpass int
80
81 set @Stock_IDpass =0
82 set @StockStatus_IDpass =2
83
84 set @ToRep_IDpass = @Rep_ID
85 set @Start_Range_IDpass = @Start_RangeID
86 set @End_Range_IDpass = @End_RangeID
87 set @Product_IDpass = @Product_ID
88
89
90 exec wc_Stock_Update 0,2,@Rep_ID, @Start_RangeID, @End_RangeID, @Product_ID,0
91
92 END
93 ELSE
94 BEGIN
95 DECLARE @Start_Serial_No int ,@End_Serial_No int
96 SELECT @Start_Serial_No =Serial_No FROM tblSerial WHERE Serial_ID=@Start_RangeID
97 SELECT @End_Serial_No =Serial_No FROM tblSerial WHERE Serial_ID=@End_RangeID
98
99 exec wc_Stock_Update 0,2,0, @Start_RangeID, @End_RangeID, @Product_ID,1
100
101 END
102
103 END
104
105 GO