Chapter 14 Managing Devices for FortiOS 5.0 : Vulnerability Scan : Requirements for authenticated scanning and ports scanned : Windows firewall settings
  
Windows firewall settings
Enable the Remote Administration Exception in Windows Firewall. (Windows 2003, Windows XP)
Allow File and Print sharing and Remote Administration traffic to pass through the firewall. Specify the IP address or subnet of the Fortinet appliance that is performing the vulnerability scan. (Windows Vista, 2008)
For each of the active Inbound Rules in the File and Printer Sharing group, set the Remote IP address under Scope to either Any IP address or to the IP address or subnet of the Fortinet appliance that is performing the vulnerability scan. (Windows 7)