RE: Durango is Dead (battery?)
Brown, that's good information, but it has nothing to do with the problem he's having. You described completely different symptoms.
Mortikai, as others have said, those terminals definitely need to be cleaned up, and you'll need to take them off to do it right. I've seen much worse corrosion, though, that didn't stop the vehicle from starting, so I really suspect you just need a new battery. Disregard the age of the battery, some die early, and some last for 15 years. Also, those portable power packs vary a lot in quality. Given that your battery is pretty much 100% drained and that you're trying to crank a big V-8 (and possibly a very cold one, depending on where you live), it may be that the one you have just doesn't have the juice to pull it off. I'd try jumping it from another vehicle.
Also, in addition to the dielectric grease or axle grease that was mentioned, I've had success using plain ol' Vaseline on battery terminals. Mainly you're just looking for something that will keep the air away from them to prevent the corrosion from returning.
One other question. Are you sure you're reading the instructions for your jump starter correctly? I can't think of any situation in which it makes sense to disconnect the positive battery cable when you're jump starting it. Running a vehicle with no battery connected is generally a very bad idea.