Normally Dail groups are created at startup, or if the environment is updated via updtdalienv. On startup, Dali checks if the Cluster's in current Environment matches the Environment it's loading from environment.xml - if they match - it does not bother to create the associated Group.
If the Environment has somehow been manually made to match the loaded environment, then this will result in the Group never being created.
Dali should also force the creation if the Group is missing.