Hello Steven,
No worries, actually, because it is asking for your new information. We have no use for the old. Just put in your new eBay ID. If you find that it doesn't work, that means you need to test it at eBay, to make sure they aren't putting up a dialog.
So in summary, after you log into BidSlammer (that ID is separate), then you are taken to the Preferences, where you enter the new eBay info.
Let us know if we can help further!
bidslammer