Is the question: do you think that Eru is God? Or is it: do you think Tolkien thought that Eru is God?
If it's the first one, I can say 'no' right away. Eru is just too far from the God that
I know.
Esty and
Gurthang make some excellent points about that.
If the poll is about the latter one, I say that I don't know (where's that option, anyway
), and I understand
Kuruharan's opinion that the question may be "unanswerable".