Please make sure you have put the old backup files to the same disk (same drive letter) when you did the backup.
For example, if you backed up your files to F:\ disk before, then when you want to restore it, you must make sure the backup files are still in F:\ disk), then you could browse it out in BackItUp when you want to restore.
If you are not sure which drive letter it is, please just send us the BackItUp logs, we will check it for you.
You could get logs in the following path, xxx is your computer name.
Give us logs files under folder: 'Jobs','Log','AppSettings.xml'.
C:\Users\xxx\AppData\Roaming\Nero\Nero xxx\Nero BackItUp
(To get into the AppData folder just type %appdata% into your Windows Browser bar.)
Thanks for your supporting of Nero!
Nero Support Team