When upgrading from prior IOS 8.4 to 8.4(4) and 8.4(5), the configuration will be converted for the new IOS without any problems. But when you’re creating a new Network Object NAT rule, you’ll get a nasty error:
ERROR: NAT Policy is not downloaded
There’s no solution for this error at this point (january 2013), Cisco TAC mentioned me that the development team is still working on this issue but it’s hard for them to reproduce this error in their lab.
But.. there is a workaround available!