You may experience the following issue when deploying your K2 Package:
Full error message: "[FieldName]: Object reference not set to an instance of an object."
This problem will occur if your Description value for your Environment Field is empty:
The developers have identified this as an issue and it will be resolved in a future version of K2.
During the deployment stage you can change the values of the Environment fields by Right clicking on the relevant field and select change value, and give it a value:
Your package will then deploy successfully: