I restored my iPad running 5.0.1 and used to redsn0w_mac_0.9.10b5c jailbreak. Everything functions normally, but appstore, itunes, and youtube crash at startup, but run in safe mode.
That indicates that you have installed a tweak from Cydia which is not compatible with the iPad. You need to tell us what you have installed and we'll see if we can help.
