1. Check if the firewall is active.
   1. Go to Control Panel > Systems and Security > Windows Firewall.
   2. Click Turn Windows Firewall On or off.
   3. Select "Turn off Windows Firewall for both Private and Public Network settings" depending on which network is attached to the Officescan Server.
2. Check if you are able to connect to machine's Administrative share ( \\machine_name\c$ ):
   1. Go to Network and Sharing Center > Change Advanced Sharing Settings and select "Use user accounts and passworkds to connect to other computers."
   2. Open REGEDIT then go to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
   3. Create a QWORD (64-bit) called LocalAccountTokenFilterPolicy then set the value to "1".
   4. REBOOT the machine.

If the steps above does not work, allow your Windows 8 machine to join the domain and use the Domain Administrator credentials to log in and perform the remote installation.