Disks set as independent can't be backed up with snapshot-based backup utilities like vBackup.
[NFC ERROR] Failed to create disk C:\Users\Administrator\Desktop\backup\ARMG2
69\170126_110839\SERVER-000001.vmdk: There is not enough space on the file syst
em for the selected operation (13).
[NFC ERROR] NfcFile_Open: Open failed:
[NFC ERROR] NfcReceiveFile: failed to open file
Failed to convert disk: The specified virtual disk needs repair (0xe00004650)
I think you will want to focus your attention on the last part of the error message. You might try the following:
1) Make full backup of your virtual machine (vSphere Client > Datastore Browser > download all VM files to desktop)
2) Power down the virtual machine
3) Logon to ESXi console (or remote via SSH)
4) Change to folder where VM is located
5) Check if vmkfstools reports that the disk image needs repair
vmkfstools --fix check diskname.vmdk
6) If vmkfstools reports that the disk image needs repair
vmkfstools --fix repair diskname.vmdk
Hope this helps.