StreamReader cannot find the path

hi
Am using direct folder path to get the file.
but the streamreader cannot be find the path it throw an exception
Could not find a part of the path Below am given my code

string strJSFile ="~/Artfiles"+ Path.ChangeExtension(l_dsresult.Tables["Table2"].Rows[0]["FileName"].ToString(), "js");
StreamReader oRead = new StreamReader(strJSFile);

Thanks & Regards
Bhuvana