Problems with applying Asset Package

[TorbjørnDalløkken2]

Hi.

I've created a new asset package to represent my water network, and I've staged the network. When I try to apply the asset package I get this error: 

I can't see any object in featureclasses (from asset package) which has a NULL-value in neither the assetgroup or assettype fields.

Does anyone know what might be wrong and how I can solve this?

[ManviLather]

Hello, 

I was working with electric data and encountered a somewhat same error message. 

ERROR 000224: Cannot insert features
ERROR 000224: Cannot insert features - The value of the subtype code is NULL. [ (class name: XXXX_TerminalTest.UNOWNER.ElectricDistributionJunction, oid: -1)]

So, I deleted the entire data from the geodatabase -> Ran the "Stage Utility Network" and then "apply Asset package from the scratch.