Cannot deploy to datastore cluster

I'm trying to import a OVA file using the tool, but I cannot seem to import it to a datastore cluster. If I don't specify the datastore, I get this:

Error: No target datastore specified. Possible completions:

  DS-CLUSTER1 (datastore cluster)

    - DATASTORE1

    - DATASTORE2

  DS-CLUSTER2 (datastore cluster)

    - DATASTORE3

    - DATASTORE4

So I try adding the datastore cluster to my command: ovftool --acceptAllEulas --datastore="DS-CLUSTER1" "c:\path\to\vm.ova" vi://user:pass@vcenterip/dc/host/cluster/Resources/resource

But it comes back with the error: Found no hosts in target cluster to deploy on. Cannot deploy to an empty cluster.

I tried with the datastore name rather than the datastore cluster name and it still fails. Any ideas?

Thanks.