Here's the response I got from the Google support:

I understand that you're receiving notification errors and have currently
integrated using BVC5. I've looked into your account and it appears that
you're receiving HTTP 500 errors. This indicates that some error is
occurring internally on your server, possibly with your googlenotify.aspx
handler. Unfortunately, I don't have intimate knowledge about what would
cause the error in your BVC5 Google Checkout handler. Please direct this
question to BVC5 themselves, as they should be able to provide more
information about their product.


And here's the Errors in my BVC5 Event Log:

5/21/2007 7:19:55 PM Error <br>Session:<br>To:https://store.attachedtobaby.com/googlenotify.aspx <br>From:<br>User:64.233.166.136(64.233.166.136)<br>Agent:Google Checkout Notification Agent 1.0
5/21/2007 7:19:55 PM System.Data There is no row at position 0.[ at System.Data.RBTree`1.GetNodeByIndex(Int32 userIndex) at System.Data.DataRowCollection.get_Item(Int32 index) at BVSoftware.Bvc5.Core.Orders.Order.Mapper.FindByThirdPartyOrderId(String ThirdPartyOrderId) in C:\development\bvc5sp2Hotfixes\BVSoftware.Bvc5.Core\Orders\Order.vb:line 2282 at BVSoftware.Bvc5.Core.Controls.GoogleNotificationProcessor.ProcessOrderStateChangeNotification(String content) in C:\development\bvc5sp2Hotfixes\BVSoftware.Bvc5.Core\Controls\GoogleNotificationProcessor.vb:line 253 at googlenotify.Page_Load(Object sender, EventArgs e) at System.Web.UI.Control.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) ]

I don't even know how to figure out if it is related to a particular order. I just get a few every hour.

When I first started Google Checkout, I had no directions to go by and did a few test orders without fully configuring everything right in the shop admin, I deleted them, but maybe Google is trying to update them still?

I think the problem you are experiencing and I don't have any familiarity with Google Checkout so my guess is based on the googlenotify.aspx code alone is that google checkout continually sends order update requests to your store trying to modify its order status. I have a feeling that you either just deleted the orders from bvc5 and not in the google checkout. Or you deleted then from bvc5 first and then googlecheckout and now googlecheckout is trying to notify your store that the order was cancelled and since the order was deleted it cannot find the order. Based on the fact that BVSoftware.Bvc5.Core.Controls.GoogleNotificationProcessor.ProcessOrderStateChangeNotification is the function being run, I'm guessing the second situation is what has happened. I do not know if the e-mails can be stopped from Google until it successfully receives an acknowledgement.

you can force the acknowledge to occur (I think) by modifying the googlenotify.aspx file in this section

Case "order-state-change-notification"
If BVSoftware.Bvc5.Core.Controls.GoogleNotificationProcessor.ProcessOrderStateChangeNotification(inputStream) Then
processedNotificationRequest = True
End If

update it with a try catch block like this

Case "order-state-change-notification"
Try
If BVSoftware.Bvc5.Core.Controls.GoogleNotificationProcessor.ProcessOrderStateChangeNotification(inputStream) Then
processedNotificationRequest = True
End If
Catch
processedNotificationRequest = True
End Try

I highly recommend that after all the orders are flushed that that code be removed and it is not very thorough in checking the exact type of error that occurred. Although an update from bvsoftware would probably be nice to handle the situation where an order no longer exists in bvc5 when a google notification is sent.

You should probably do Andy's suggestion first before applying my code to ensure that only the deleted orders are causing the issue.

On an interesting side note and since I do not currently use google checkout I cannot really issue any type of testing. But it appears the process function actually checks if the order exists prior to attempting processing and it is on this check that the error is thrown (more of a reason to use andy's suggestion first). I have a feeling that an empty table to being created when the Stored procedure returns no data (if my theory regarding the order being deleted in bvc5 is correct) when it should not be (based on the logic in the findbythirdparty function).