This error implies the system is not being seen as a clustered environment. Please ensure that the 'Failover Clustering' Feature has been installed on both server nodes, via the Add Roles and Features Wizard.
You have not said what version of DLO or OS you are using, but please review Pages 212-217 of the DLO 9.5 Admin Guide (DLO_95_AdminGuide) for guidance on how to setup DLO in a cluster.
Basically DLO needs to be installed standalone with a local SQL instance on each node and a cluster Shared Disk available to eventually hold the clustered DB. The DLO Cluster Configuration Utility is then run on the Active node and configured to cluster DLO on both nodes, to a new Virtual Server (Role). As part of that, the DB is then moved to the Shared Drive and registry is reconfigured, so that each node, when Active, accesses the shared DB after failover. You should then go on to configure Storage, Profiles and Users.
Please note there was an issue seen with DLO 9.4 where the DLO Cluster Configuration Utility would not run, due to a mismatched file name (discussed in https://www.veritas.com/content/support/en_US/article.100048349), but that was resolved in the recent DLO 9.5 release and does not appear to be the error you are getting.