I answered this in my very first response (please reread it): You must obtain an original copy of the app from Adobe. It is very old, and therefore hard to find. Others here recognize the level of difficulty, hence the many suggestions to consider alternatives.
There are very few documents out there that are 1.0 compatible, anyway, so the only things you will be able to read are ones that you produce yourself. Given that situation, you'd be far better off simply creating documents in some other format, in my opinion. But if you are obsessed with the notion of producing v1.0 documents, I've given you the only known method for doing so.