Logs an import error message to the console.
Pass an asset as the second argument to link the error to the asset in the editor.
See Also: Debug.LogError.
    class CustomImportSettings extends AssetPostprocessor {
    function OnPreprocessTexture() {
        var importer : TextureImporter = assetImporter;
        if(!importer)
            LogError("Texture doesnt exists");
    }
}