Well, I figured out my problem with the IHG app.
There are multiple "apps" out there for IHG and holiday inn. However, it appears that only the IHG App for Android (available from the google play store) is the one that counts.
I do not have an android phone, so I can't download that app (and neither can Nokia phone owners, Blackberry owners, etc..) (and, thanks for the ideas to use someone else's phone, but android apps require syncing your google accounts to the device, and I don't really know anyone well enough to give them my google passwords, emails, contacts, etc.).
So... no go for me, I will have to let that one pass me by.
My advice for IHG Promo is to make it more clear in their initial offers that this is a very specific item, rather than use the generic word "app". "Download the Android App from Google and book a stay", rather than "Download the app".
I'll see if I can find a hotel on my travel route now that has a breakfast rate I can book, to complete that one. That's even harder, given the remote locations I tend to stay (mostly HIE locations only). But, there's a chance, perhaps, to find one and complete that instead.