Do not ask Papa Roach if you can use their stuff under any circumstances. If it's local to you, chances are you'll have to bring your own backline. If I were you, I'd set up quickly and efficiently without making too much noise (you may not even get much of a soundcheck for a gig like that), don't complain even if things aren't to your liking, and generally just act like a professional. When the soundman asks you to do your line/monitor checks, nobody should play but the person who he's checking at that moment (this is a major source of irritation for a soundman and makes you look bush league if you play over someone else's line check). Always say "please" and "thank you" when you request something from the soundman. Then do whatever soundcheck they give you and get off the stage immediately when you're done and don't come back until showtime. And if the soundman says you need to turn down, for God's sake, do it
But most of all, act like you belong there. You're an act on a big show, so conduct yourself like a big act. If you meet the guys in Papa Roach, don't act like a fanboy. Just thank them, maybe strike up a short conversation if you have time, and don't hassle them for pictures/autographs until you're sure it's cool. And approach everything you do with the confidence of a band that deserve to play in front of a couple thousand people. Confidence, not arrogance.
Anyway, I know I went on a little longer than you may have wanted, but if you want more opportunities to do stuff like this, I can't tell you how important it is to conduct yourself like you belong there.