Error : Invalid Resx file

Assembly assembly = Assembly.GetExecutingAssembly();
ResourceManager rm = new ResourceManager("NameSpace.Demo", assembly, null);
logo.Image = (Image)rm.GetObject("WroxLogo");
textTitle.Text = rm.GetString("Title");
catch (Exception ex)

Hi, I created a Demo.resx and I included it to my project, when I try to compile it showing.
Error :Invalid Resx file. Invalid character in the given encoding. Line 1, position 1. <File Path>\Demo.resx
Can any one explain why this error is occurring and how to rectify it?

Front-end : C# 2005