Texture importer API doesn't work on build exe

when i run the game at Runtime, it works. at runtime it download images to Resources Folder and set the resolution to 4096x4096, set the texture type to GUI and apply them to material of 3d model.

if i try to build the game Standalone exe , i get errors. i can't build it.

the picture shows that the error messages while publishing to Standalone exe

and the script that i use for Texture Importer API

  string path = "Assets/Resources/Data/Models/" + ModelID + "/Model.jpg";
  TextureImporter importer = (TextureImporter)TextureImporter.GetAtPath(path);
  importer.textureType = TextureImporterType.GUI;
  importer.mipmapEnabled = false;
  importer.maxTextureSize = 4096;
  importer.SaveAndReimport();