You can't play the game because either some of its files are corrupted or your computer doesn't meet the minimum system requirements. In order to play it, check the minimum requirements for Xian Online:
- OS: Windows 2000, Windows XP;
- RAM: 128MB;
- CPU: Intel Celeron with 1GHz or Pentium 4;
- Free HDD: 2GB;
- Video Card: Intel Extreme GFX2 or similar;
- DirectX 8.1 or higher.
If the requirements are fulfilled, update your video card drivers, install the latest version of DirectX and reinstall the game.
If you still have issues, go to Start > Control Panel > System and Security > Windows Firewall > Allow a program through Windows Firewall and check the box next to Xian Online. If you can't find the game in the Allowed programs and features window, press the Allow another program button, navigate to the installation directory, select the executable file and press Add. After that, from the Advanced Settings select Inbound Rules > New Rule. Check the Port box, click Next, select All local Ports and follow the self-explained steps. Also, make sure that your security program doesn't block the connection.