You get this error, when you use neutral culture name to set culture of the application.
1 System.Globalization.CultureInfo ci = new System.Globalization.CultureInfo("tr");
2 System.Threading.Thread.CurrentThread.CurrentCulture = ci;
3 System.Threading.Thread.CurrentThread.CurrentUICulture = ci;
To prevent this error you can use explicit culture name like "tr-TR" or use the code below:
1 System.Globalization.CultureInfo ci = System.Globalization.CultureInfo.CreateSpecificCulture("tr");
Happy coding.
