Runtime Error

Hi

I have written this , it is giving me this error

Run-time error'-2147217900(8004e14)'
[Microsoft][odbc Sql Server Driver][Sql Server] Backup Database
WeighBridge To DISk = 'd:\Backup'

Secondly i want if Stored Procedure is executed successfully it should return value so that message should be displayed .

Private Sub cmdbackup_Click()
Dim res As Integer
Set cmd = New ADODB.Command
cmd.ActiveConnection = cnn1
cmd.CommandType = adCmdStoredProc
cmd.CommandText = "sprocFullBackup"
cmd.Parameters.Append cmd.CreateParameter("databasename", adVarChar, adParamInput, 256, "Test")
cmd.Parameters.Append cmd.CreateParameter("folder", adVarChar, adParamInput, 256, "d:\")
cmd.Parameters.Append cmd.CreateParameter("foldername", adVarChar, adParamInput, 256, "Backup")
cmd.Execute
End Sub

Stored Procedure is this
'----------------------
ALTER PROC [dbo].[sprocFullBackup]
@DatabaseName VARCHAR(256),
@Folder VARCHAR(256),
@FileName VARCHAR(256)
AS
BEGIN
DECLARE @DynaSql NVARCHAR(MAX)
IF RIGHT(@Folder,1) != '\'
SET @Folder = @Folder + '\'
SELECT @DynaSql = 'BACKUP DATABASE ' + @DatabaseName + ' TO DISK = ' +
CHAR(39) + @Folder + @FileName + CHAR(39)
PRINT @DynaSql
EXEC sp_executeSQL @DynaSql
END