They are the same thing (
From the full scan, since part of the text is missing)
我は正に胡蝶 ーーー 邯鄲の夢の中に在り一炊の夢に過ぎない存なき夢幻泡影の如し
I'm undoubtedly a butterfly... Existing within the Dream of Handan, nothing more than an empty dream, like a dream, illusion, bubble, or shadow that doesn't exist.
"
Dream of Handan" (邯鄲の夢) seems to be talking about an old Chinese play about a person who sleeps and thinks to have lived an entire life when it was actually just a dream
"
夢幻泡影" is a common idiom from Chinese and It's made of kanjis for dream, illusion, bubble, and shadow. it's basically supposed to talk about the way in which reality is a temporary illusion, so it mentions various terms like that, which is understood thanks to "存なき" (Kanji for existing, "存", with the suffix for a negative form "なき", so it means non-existing, that which does not exist).
Unsure of an easy way of translating that keeps all the nuance, but I guess this explanation makes it clear for you. I guess "Non-existing dream bubble" could work.
So:
I'm undoubtedly a butterfly... Existing within the Dream of Handan, nothing more than an empty dream, like a non-existing dream bubble.