Creating Topology

While creating topology on versioned dataset giving us below error ""Cannot create Topology. The selected Feature Dataset does not contain any feature classes which can participate in a topology"

So i got to know that before creating topology we need to unregister it. Is unregistering a dataset causes any issues?

and after creating topology with some set of rules. when i generate summary i am getting lot of errors for the given set of rules.

what i need to do with this errors with generate summary.

Appreciate some quick solutions.

Regards,
Suraj