I need help with Marketplace Service [Still Un-answered] please?

The short of it is, I don't recieve money on purchase.

What I have running, in ServerScriptService, as a Server-Sided Script:

-- setup local variables
local MarketplaceService = Game:GetService("MarketplaceService")
local ds = game:GetService("DataStoreService"):GetDataStore("PurchaseHistory")

-- define function that will be called when purchase finished
MarketplaceService.ProcessReceipt = function(receiptInfo) 

    -- find the player based on the PlayerId in receiptInfo
    for i, player in ipairs(game.Players:GetChildren()) do
        if player.userId == receiptInfo.PlayerId then

        -- check which product was purchased
            player.Teleport.Value = false wait() player.Teleport.Value = true
        end
    end 

    -- record the transaction in a Data Store
    local playerProductKey = receiptInfo.PlayerId .. receiptInfo.PurchaseId
    ds:IncrementAsync(playerProductKey, 1)  

    -- tell ROBLOX that we have successfully handled the transaction
    return Enum.ProductPurchaseDecision.PurchaseGranted     
end

This was copied from the demo place I found in the Roblox Wiki (http://www.roblox.com/Developer-Product-Sample-place?id=147965737).

the local 'playerProductKey' (line 14) used to be longer, but used to produce errors: 'key is too long' or something.

Shortening that fixed the errors, but still it won't pay me.

Please tell me if you see something that may cause this to not work.