OK, I've looked it up. "Ou" with an accent on the U means "where". So, literally, the phrase translates "all well where well".
But what exactly it is supposed to mean is an interesting question. The phrase is obviously contracted. It could be something very akin to "All's well that ends well" (although not having exactly the same sense). It may even be possible that "bien" has multiple meanings, and the phrase could be a play on words. I think you would have to ask a native French speaker.