This is specific to SEA client only, a statement from SEA support.
We are aware that some of the popular mods are not working for the Asia game client and are currently investigating the issue.
In the meantime, please do not install mods for the 9.20.1 update.
If you have already installed mods, please clean folders /res_mods/0.9.20.1/ and /mods/0.9.20.1/ or just run the game in safe mode.
We thank you for your patience and kind understanding. World of Tanks Asia.