It won't fail
It works on my old iPhone 3G with OS3 with no problems.... The only thing is you can only do one book at a time. Another way is if you have web space (I have my own domain and use it for books for my daughter) you can upload books to a directory... and type in the URL for that directory in the "add book source" part to my guide above....That way all books show up in that directory and you can download them. Also you might try putting books in the "public" folder in Dropbox, and then putting that URL in the "add book source" in Stanza.... I bet it would work....