xna 4.0 - SpriteFont Exception, no such character?

I have such spriteFont:

  


    
    Segoe UI

    

    20

    
    0

    
    true

    
    


    
    

    
    
      
        	
        	
      
      
         

        Ұ
      
    
  

It has the character regions (32-1200)

And I get this exception:

A first chance exception of type 'System.ArgumentException' occurred in Microsoft.Xna.Framework.Graphics.ni.dll

The character 'с' (0x0441) is not available in this SpriteFont. If applicable, adjust the font's start and end CharacterRegions to include this character.

Parameter name: character

Why?

I'm drawing the string like this:

spriteBatch.DrawString(font24, zasadyText, zasadyTextPos, kolorCzcionki1, -0.05f, Vector2.Zero, 1.0f, SpriteEffects.None, 0.5f)

I even changed the spriteFont to cyrillic:

    
      
        	
        	

      
      
         
        ſ
      
      
        А
        ї
      
    

  

and it still doesn't work. I got the (0x441 => char) exception

-- EDIT --

Ok, I got the solution. It was a letter mistake in language. I had this:

if (jezyk == "ru_RU")
{
    font14 = Content.Load("ru_font14");
    font24 = Content.Load("ru_font24");

    font12 = Content.Load("ru_czcionkaFloty");
    font10 = Content.Load("ru_font10");

    font28 = Content.Load("ru_font28");
    font20 = Content.Load("ru_font20");
}

else
{
    font14 = Content.Load("font14");

    font24 = Content.Load("font24");
    font12 = Content.Load("czcionkaFloty");
    font10 = Content.Load("font10");

    font28 = Content.Load("font28");
    font20 = Content.Load("font20");
}

and there should be not "ru_RU" but "ru-RU"

---

I have no idea. I changed the spriteFont to cyrillic:

    
      
        	
        	
      
      
         
        ſ
      

      
        А
        ї
      
    
  

and it still doesn't work. I got the (0x441 => char) exception