HELP Can't create new worksheet in Excel via automation

I can create a new worksheet in Excel using automation by not pasing any arguments in the Add method but I need to be able to insert a newsheet betwen sheets as the arguments suggest: Add( before, after, count, type). Where before = which existing sheet to place the new sheet in fornt of, after = where to place the new sheet behind, count = how many new sheets, and type is the typeof sheet which I am told the value = -4167, When I tried to do this I get the error message: "Insert New Sheet Class Failed" What am I doing wrong?

Thanks

Jim Bassett