Assuming the VeeamBackup datastore is present and not being used the first troubleshooting step for this error should be to Unmount the VeeamBackup datastore and then try again the tasks that threw the error.
Below are the three most common causes of this issue and their respective resolutions.
This occurs when you manually select a resource pool for a Veeam component and the resource pool does not have enough memory allocation to accommodate this VM
Resolution: Increase the memory allocation to the resource pool or do not use a predetermined resource pool and use the top tier ‘Resource Pools’ and let it self assign.
This can occur when restoring a VM, including SureBackup, that was backed up with Veeam Backup & Replication version 18.104.22.1685 or older, to a vSphere 5.5 environment.
Resolution: This configuration is unsupported, any restores from this cannot be guaranteed. It is advised that you install the most recent patch. http://www.veeam.com/patches.html.
More information regarding resolving this error when it occurs during SureBackup can be found at www.veeam.com/KB1826.
A similar issue can occur if the NFS datastore location/location you specified for Virtual Lab does not have enough free space to create the swap file.
Resolution: Investigate and resolve any free space issues that may be occurring.