Backdoor.Rewdulon.B is one of the names for it, it is basically a trojan downloader

Could you go to C:\qoobox

and upload to Avast via the virus chest any files that have this format windows\SysWOW64\api-ms-win-core-io-l1-1-032.dll

Start Avast and select Maintenance > Virus chest
Click in the white space and select add
Navigate to qoobox and add the files one at a time
Once they are in the chest then right click the files and select send to virus lab

Once you are happy that all is good let me know and I will remove my tools