First, check if your friend computer meets the minimum system requirements to play AION:
- OS: Windows XP (SP3) Windows XP x64 (SP2), Vista (SP2), Windows 7 (SP1)
- CPU: Intel Pentium4 2.8 GHz / AMD Sempron+ 2800;
- Video Card: NVIDIA Geforce 6800 GT/ AMD Radeon X800 XL;
- RAM: 1GB;
- Free Hard Disk Space: 40GB;
- DirectX: 9.0c(2008. 6).
Also, make sure that the antivirus and Windows firewalls allows AION to connect to servers. If the connection is blocked by Windows firewall you can configure it using the guide provided by Microsoft. If the requirements are fulfilled and the connection is not blocked you will need to get in touch with AION Support Team in order to solve the issue.