Conversion Failed When Converting The Varchar Value

why do i have this error? not converting a varchar into int 1 ALTER PROCEDURE dbo.RevertDB
2 (
3 @Log varchar(MAX) = NULL OUTPUT
4 )
5
6 /* Reverts Database to original "Clean" State */
7 AS
8 SET NOCOUNT OFF
9 DECLARE @RowsInDB AS int
10 SET @Log = 'RevertDB Started at ' + CAST(GETDATE() AS varchar(50)) + '<br />'
11
12 /* *** Disable Constraints ***
13 ALTER TABLE Booking NOCHECK CONSTRAINT ALL
14 ALTER TABLE InventoryPC NOCHECK CONSTRAINT ALL
15 ALTER TABLE PC NOCHECK CONSTRAINT ALL
16 ALTER TABLE Platform NOCHECK CONSTRAINT ALL*/
17
18 /* *** Start Deletes *** */
19 DELETE FROM Booking
20 SET @Log = @Log + 'Clear Table Booking - Done' + '<br />'
21 SET @RowsInDB = (SELECT COUNT(BookingID) FROM Booking)
22 SET @Log = @Log + '-- Rows Affected: ' + CAST(@@ROWCOUNT AS varchar(10)) + ', Rows in Table: ' + CAST(@RowsInDB AS varchar(10)) + '<br />'
23
24 DELETE FROM InventoryPC
25 SET @Log = @Log + 'Clear Table InventoryPC - Done' + '
'
26 SET @RowsInDB = (SELECT COUNT(InventoryID) FROM InventoryPC)
27 SET @Log = @Log + '-- Rows Affected: ' + CAST(@@ROWCOUNT AS varchar(10)) + ', Rows in Table: ' + CAST(@RowsInDB AS varchar(10)) + '<br />'
28
29 DELETE FROM PC
30 SET @Log = @Log + 'Clear Table PC - Done' + '<br />'
31 SET @RowsInDB = (SELECT COUNT(PCID) FROM PC)
32 SET @Log = @Log + '-- Rows Affected: ' + CAST(@@ROWCOUNT AS varchar(10)) + ', Rows in Table: ' + CAST(@RowsInDB AS varchar(10)) + '<br />'
33
34 DELETE FROM Platform
35 SET @Log = @Log + 'CLear Table Platform - Done' + '
'
36 SET @RowsInDB = (SELECT COUNT(PlatformID) FROM Platform)
37 SET @Log = @Log + '-- Rows Affected: ' + CAST(@@ROWCOUNT AS varchar) + ', Rows in Table: ' + CAST(@RowsInDB AS varchar(10)) + '<br />'
38
39 /* *** Enable Constraints ***
40 ALTER TABLE Booking WITH CHECK CHECK CONSTRAINT ALL
41 ALTER TABLE InventoryPC WITH CHECK CHECK CONSTRAINT ALL
42 ALTER TABLE PC WITH CHECK CHECK CONSTRAINT ALL
43 ALTER TABLE Platform WITH CHECK CHECK CONSTRAINT ALL*/
44
45 SET @Log = @Log + '*** End Truncates ***' + '<br />'
46 /* *** End Truncates *** */
47
48 /* *** Start Insert Platform *** */
49 SET @Log = @Log + 'Start Insert Platform' + '<br />'
50
51 EXEC dbo.InsertPlatfrom 'Windows XP SP2 Professional Edition', 'Some description for Windows XP SP2 Professional Edition over here …'
52 EXEC dbo.InsertPlatfrom 'Windows Vista Ultimate', 'See everything you''re working on more clearly with Windows Aero, and quickly switch between windows or tasks using Windows Flip 3D and Live Thumbnails. You can easily find what you need—when you need it―with Instant Search and live icon previews that display the actual contents of your files. And while you''re at it, give your personal productivity a boost with instant access to the information you care about using Windows Sidebar and Gadgets. Put these easy-to-use and customizable mini-applications on your desktop and reveal the information you''re looking for at a glance. Website: http://www.microsoft.com/windows/products/windowsvista/seeit/default.mspx'
53 EXEC dbo.InsertPlatfrom 'Apple Mac OS X Tiger', 'Some description for Apple Mac OS X Tiger over here …'
54 EXEC dbo.InsertPlatfrom 'Apple Mac OS X Leopard', 'Desktop: The new look of Leopard showcases your favorite desktop image and puts new file Stacks at your fingertips for a stunning, clutter-free workspace. Finder: Browse your files like you browse your music with Cover Flow. Time Machine: See how your system looked on any given day and restore files with a click. Website: http://www.apple.com/macosx/leopard/features/'
55 EXEC dbo.InsertPlatfrom 'Red Hat Linux', 'Some description for Red Hat Linux over here …'
56
57 SET @Log = @Log + 'Rows In Platform: ' + CAST((SELECT COUNT(PlatformID) FROM Platform) AS varchar(10)) + '<br />'
58 /* *** Start Insert PC *** */
59 SET @Log = @Log + 'Start Insert PC' + '<br />'
60
61 DECLARE @WinXP int, @WinVista int, @OSXTiger int, @OSXLeopard int, @RedHat int
62 SET @WinXP = (SELECT PlatformID FROM Platform WHERE Title = 'Windows XP SP2 Professional Edition')
63 SET @WinVista = (SELECT PlatformID FROM Platform WHERE Title = 'Windows Vista Ultimate')
64 SET @OSXTiger = (SELECT PlatformID FROM Platform WHERE Title = 'Apple Mac OS X Tiger')
65 SET @OSXLeopard = (SELECT PlatformID FROM Platform WHERE Title = 'Apple Mac OS X Leopard')
66 SET @RedHat = (SELECT PlatformID FROM Platform WHERE Title = 'Red Hat Linux')
67
68 EXEC dbo.InsertPC 'Fusion PC One', 'Description here ...', 'Intel Core2 Duo E6600 2.4 GHz 1066MHz', '1GB Dual Channel DDR2 667 SDRAM', '120GB SATA2 NCQ HDD', 'NVIDIA GeForce 8600 256MB GDDR3', '22" 3000:1 Wide Screen LCD', @WinXP
69 EXEC dbo.InsertPC 'Fusion PC Two', 'Description here ...', 'Intel Core2 Duo E6850 3 GHz 1333MHz', '2GB Dual Channel DDR2 800 SDRAM', '240GB SATA2 NCQ HDD', 'NVIDIA GeForce 8800 Ultra 256MB GDDR3 SLI', '24" 3000:1 Wide Screen LCD', @WinVista
70 EXEC dbo.InsertPC 'Fusion PC Three', 'Description here ...', 'AMD Athlon 64 X2 Dual Core 6000+ 3 GHz', '2GB Dual Channel DDR2 667 SDRAM', '240GB SATA2 NCQ HDD', 'ATI Radeon Cross Fire 2900 256MB GDDR3', '24" 3000:1 Wide Screen LCD', @WinVista
71 EXEC dbo.InsertPC 'Fusion X1', 'Description here ...', 'Intel Core2 Extreme Q6850 3 GHz 1333MHz', '6GB Dual Channel DDR2 800 SDRAM', '500GB SATA2 NCQ HDD', 'NVIDIA GeForce 8800 Ultra 256MB GDDR3 SLI', '30" 3000:1 Wide Screen LCD', @OSXLeopard
72 EXEC dbo.InsertPC 'Fusion X2', 'Description here ...', 'AMD Athlon 64 FX 74 3 GHz', '6GB Dual Channel DDR2 800 SDRAM', '500GB SATA2 NCQ HDD', 'NVIDIA GeForce 8900 Ultra SLI 256MB GDDR3', '30" 3000:1 Wide Screen LCD', @WinVista
73 EXEC dbo.InsertPC 'Fusion Tiger 1', 'Description here ...', 'Intel Core2 Duo E6600 2.4 GHz 1066MHz', '2GB Dual Channel DDR2 800 SDRAM', '120GB SATA2 NCQ HDD', 'NVIDIA GeForce 8600 256MB GDDR3 SLI', '22" 3000:1 Wide Screen LCD', @OSXTiger
74 EXEC dbo.InsertPC 'Fusion Linux 1', 'Description here ...', 'AMD Athlon 64 X2 6000+ 3 GHz', '1GB Dual Channel DDR2 800 SDRAM', '120GB SATA2 NCQ HDD', 'NVIDIA GeForce 8600 256MB GDDR3', '22" 3000:1 Wide Screen LCD', @RedHat
75
76 SET @Log = @Log + 'Rows In PC: ' + CAST((SELECT COUNT(PCID) FROM PC) AS varchar(10)) + '<br />'
77
78 /* *** Start Insert Inventory *** */
79 SET @Log = @Log + 'Start Insert Inventory' + '<br />'
80
81 DECLARE @F1 int, @F2 int, @F3 int, @FX1 int, @FX2 int, @FT1 int, @FR1 int
82 SET @F1 = (SELECT PCID FROM PC WHERE Title = 'Fusion PC One')
83 SET @F2 = (SELECT PCID FROM PC WHERE Title = 'Fusion PC Two')
84 SET @F3 = (SELECT PCID FROM PC WHERE Title = 'Fusion PC Three')
85 SET @FX1 = (SELECT PCID FROM PC WHERE Title = 'Fusion X1')
86 SET @FX2 = (SELECT PCID FROM PC WHERE Title = 'Fusion X2')
87 SET @FT1 = (SELECT PCID FROM PC WHERE Title = 'Fusion Tiger 1')
88 SET @FR1 = (SELECT PCID FROM PC WHERE Title = 'Fusion Linux 1')
89
90 EXEC dbo.InsertInventory 10, @F1, 2.5, 'iCluster Fusion One'
91 EXEC dbo.InsertInventory 10, @F2, 2.5, 'iCluster Fusion Two'
92 EXEC dbo.InsertInventory 10, @F3, 2.5, 'iCluster Fusion Three'
93 EXEC dbo.InsertInventory 6, @FX1, 6, 'iCluster Fusion X1'
94 EXEC dbo.InsertInventory 6, @FX2, 6, 'iCluster Fusion X2'
95 EXEC dbo.InsertInventory 10, @FT1, 3, 'iCluster Fusion Tiger One'
96 EXEC dbo.InsertInventory 30, @FR1, 2, 'iCluster Fusion Linux One'
97
98 SET @Log = @Log + 'Rows In Inventory: ' + CAST((SELECT COUNT(InventoryID) FROM InventoryPC) AS varchar(10))
99
100 RETURN @Log
 
 if i remove the last line then all is well. but i get "An SqlParameter with ParameterName '@Log' is not contained by this
SqlParameterCollection."