I’ve been watching, and I’ve seen is in torrent and gnutella networks (emule) the OperaBackup installer .. and I saw that some of these downloads include a virus that can infect your computer.

operabackup-4.0.0.3.exe
Trojan/Win32.Buzus.gen 

I always recommend for download from the official site (cjcr-soft.com) to avoid such problems.
I am not responsible if you are infected with a virus, and you download the program from outside server of cjcr-soft.com.