Resque Disk offline update

Hello guys, new here! ;D
I want to use a offline PC to scan for threats.
I have a USB Resque Disk but I cannot update at last defs.
I repet the PC is offline, no hdd.
I boot from stick and when I try to run vsupdate.exe, return an error.
Please help me to update Resque Disk offline.
I have Avast Business, I receive daily update but because of so many usbsticks infected I decided to make an offline scanner.
Can you help me please update offline Resque Disk with daily updates? Thank you!!:pray: