Virus warnings

As i use this ReadyNas Ultra 2 with OS 6, but it was also present in the former firmware version, i regular get warnings about a virus on the system which produces always the same files. These are: AV.lnk AV.scr Video.lnk Video.scr and Photo.lnk Photo.scr

I don't know where this coming from and how to get rid of this problem. I searched the internet and this community but found nothing in relation with my problem.