I read a summary of the movie and it said that Fishburns character shoots at Paul walker during the exchange in the beginning. But what was his motive for that? He just releases the guy from jail just to shoot at him? The exchange for his partner hadn't even taken place yet.
You would have to see the movie from beginning to end to fully understand why Fishburns shot at Paul Walker. I too was a bit confused when watching it but it all came together. I'm guessing you want to know why, so here it goes:(SPOILER)
The reason why Fishburn shot at Paul Walker was because he needed someone who looked like Bobby Z so he could prove that Bobby Z was dead when really Bobby Z was actually alive.
I would go on and on but you really should watch it, it's a good movie.
I think the first and most important reason was money. The real Bobby Z was going to pay him to help fake his own death, but by using a real body AKA Tim.