Hello Marcos
As is usually the case, there are features and commands that are available on some platform/IOS combinations and not on others. This depends upon what Cisco decides to include in each version.
As for the ipv6 dhcp iapd-route-add command, from what I’ve seen, this is enabled by default, at least on the ASR platforms, but again, this depends upon the platform.
In order for us to help you more effectively, can you share with us the specific commands from the lesson that are not working for you on the 7301 platform?
I hope this has been helpful!
Laz