Garbled exception information in Chinese Enviornment(after rmarkdown::render )

[dwanboweb]

I use REngine to render a RMARKDOWN file encoded in utf-8 into html in a Chinese environment:

                   try
                    {
                       engine.Evaluate(@"Sys.setlocale(""LC_ALL"", ""Chinese"")")
                        string htmlFile = engine.Evaluate(@"rmarkdown::render(randerfilepath,output_file=htmlpath,encoding='utf-8')", en).AsCharacter()[0];
                        rs.sucess = true;
                        rs.htmlFile = htmlFile;
                        return rs;
                    }
                    catch (Exception ex)
                   {
                    //ex,Message garbled ,such as :   Error in library(‘gt’):???‘gt’???,
                   }

Whenever an exception occurs, the non-English part of the exception information is garbled (for example, it will prompt: Error in library(‘gt’):???‘gt’???, I guess the real error message is: missing ‘gt’ package). What should I do?
Thank you.