do I need Vcenter Server or NOT ? Esxi free edition

[g.ale]

Hello, I downloaded Veeam Backup trial version, received license file, installed ok.

I wanted to try the software on a single node Esxi server (regularly licensed but as Esxi free edition).
I'm not able to backup nothing and I do not understand this:
Do I need Vcenter Server license too for backing up with Veaam software ?
I did not have issues installing Veeam backup software, no errors and it connects ok to my Esxi server and I can create a job and starting it, but the error says:

//////////////////////////////////////
of 0 files processed

Total VM size: 53,02 GB
Processed size: 0,00 KB
Processing rate: 0 KB/s
Backup mode: NBD without changed block tracking
Start time: 16/02/2011 11.24.23
End time: 16/02/2011 11.24.29
Duration: 0:00:06


Checking the license for the source host 'ESXiR710.dbnet.spc'
Failed to validate license for the VM "halifax14022011".
Your Veeam Backup license does not allow processing of free ESXi.
////////////////////////////////////////////////////////////////////

I do not understand, this seems to be a Veeam related problem, can someone answer me clearly if Veeam Backup can be made on ESXi node without Vcenter Server license ?
I tried on a local machine installing the software and on a VM too, Veeam seems to let me choose if I I want to use Vcenter or not, so I do not understand if I got to buy it or not.
If I could backup with just Veeam software and no Vcenter server it would be so great..
Thanks everybody,

Giulio

[Gostev]

Hello, vCenter server is not required (Veeam Backup supports standalone hosts). However, the hosts must be licensed with paid VMware licence. Please review sticky FAQ topic for more information on system requirements, and minimum required VMware license levels. Thanks.

[g.ale]

Thanks so much for reply.