Open the control panel and select Allow a program through Windows Firewall
Select the Exceptions Tab and then click Add Program.
Select Browse - you need to navigate to the Yuuguu installation directory. This will be C:\Users\User Name\AppData\Roaming.
Select Yuuguu.exe and click Open. If Yuuguu.exe isn't present then you are running an older client. For more instructions, click here.
Yuuguu.exe will now have been added to your Firewall exception list. Click OK to finish.