Not sure what is the VIRL version you have, pleae check the limitation here :
CML 2.0 supports backward compatibility for .virl topologies from the 1.6 release with some limitations. You can import your legacy .virl files from your local machine to the CML server from the Lab Manager page in the new UI. In the 1.6 release, topology files generally reside on the local machine under the GUI's workspace folder. To find the local path to a particular topology file, right-click on the file in the Project view of VM Maestro or the CML UI and select Properties from the pop-up menu. The Resource > Location property provides the file location.