[Freetype] strange error codes

[Roman Bednarek]

Hi.
   In my program I get strange (I think) error codes from freetype
functions i.e.
FT_Set_Pixel_Sizes 0x80, 0x82, 0x81, 0x83, 0x86
FT_Load_Glyph 0x80, 0x81, 0x82, 0x83, 0x86, 0x87, 0x88, 0x89, 0x8C, 0x8D
FT_Render_Glyph 0x07

  I guess the error codes are not correct, and therefore I cannot diagnose
the reason. The program runs fine for some time, but after first error
occurs, there is always an error. I use few different fonts with many
different sizes, so I call FT_Load_Glyph and FT_Set_Pixel_Sizes many
times.
   I am using freetype 2.1.3 under linux. Maybe something has ended in the
freetype library?
I always call functions in the following way:

   FT_Set_Pixel_Sizes(face, a, b);
   FT_Set_Transform(face, &matrix, NULL);
   FT_UInt glyph_index = FT_Get_Char_Index(face, unicode_char);
   FT_Load_Glyph(face, glyph_index, FT_LOAD_DEFAULT|FT_LOAD_NO_BITMAP);
   FT_Render_Glyph(face->glyph, render_mode);

 Do you have any suggestions way this is happening, what I can do to fix
that problem?
  Thanks for any help.

   Roman Bednarek