Ok, I have made an app with the iPhone SDK on snow leopard, and when I click Build and Run it runs fine in the simulator, but when I try to run it on my iPod touch (upload .app from release folder to website, downloading and putting the .app in my /Applications folder then respring) I see the icon and the label fine, bit t immediately crashes. Any ideas?

Using iPhone sdk for ios 4
Ios 4.0 on iPod touch 3G
Jailbroken using JailbreakMe