You can hide Malware, trojans, viruses etc from software like AntiVir and others.
Virustotal is a Website that hackers use to check their trojans, etc.
I know many trojans where you will get a result of 0/33 from Virustotal, but the trojan works quite perfect.

@Stumickel: can you please send me the infected file?
I will disassemble that file and try to find out what it is.

just upload it anywhere and send me the link.
i would be very thanksfull