OK. We've got a few possible scenarios here.
1. She's afraid of the barrels and needs to be desensitized, or perhaps he was used for jumping in the past and they used barrels for standards (unlikely, but possible). Go back to slow work, at a walk, working around the barrels properly, and making it no big deal.
2. She's blown up and doesn't want to turn. I haven't really seen that ruined horses want to "jump," but then it's hard to picture what you're describing, anyway. If this is the case, she either needs to come off barrels completely before it escalates into rearing or worse, or else go to a very, very experienced trainer who can handle this issue.
3. She's hurting and this is her way of telling you. Get a vet out to do an examination if you suspect that this is even a remote possibility.
4. You're setting her up badly and she doesn't know what you want. I have no idea what kind of cue you're giving, but if she's trying to jump the barrels, then you're obviously too close. Remember your pocket! Remember to drive her to the correct entrance point, giving her plenty of room, and not pulling her into and on top of the barrel. Support with inside rein and inside leg. Sounds like this could very well be "operator error."