The Edge -- Too Close to the Edge During Concert ... Big Fall (VIDEO)

The Edge still can't find what he's looking for ... in this case, the rest of the stage.

U2 opened up its "Innocence + Experience" world tour Thursday in Vancouver. As the band played its iconic hit, "I Still Haven't Found What I'm Looking For" ... Edge went flying offstage.

After the show he posted he was fine, writing, "Didn't see the edge, I'm ok!! #U2ieTour." Looks like his arm is badly scraped.

The band is already operating at less than 100% -- Bono suffered a terrible bike accident in NYC last November that required two surgeries.