First of all, I'm really sorry the task doesn't work for you, it's really helpful for searching for waste left by failed migrations, backups, etc.
Let's fix it, I'm sure it should work for you (otherwise it would display an error indicating compatibility issues).
I would still check that you have sufficient permissions for the data collection account (the one which is being used to connect to vCenter in our Virtualization Extensions UI). You can check how permissions should look like here http://helpcenter.veeam.com/mp/70/vmware_guide/index.html?installation_guide.html
If you still cannot launch the task, then I'm afraid we need more information, logs, screenshots, etc. Our tech support team should be able to quickly investigate and fix the issue. I would recommend to submit a ticket at http://cp.veeam.com
Let me know if you have any other questions.