If you embed a resource in Visual Studio by linking to a file and then want to adjust the case of that link, you have to do it in two places:

Open up the project file and find the link:

<EmbeddedResource Include="..\..\..\..\Yui.zip">
   <Link>Yui.zip</Link>
</EmbeddedResource>

Ensure that both instances of the name (in this case "Yui.zip") have the same case.  The text you specify in the "Include" attribute is what shows up in Visual Studio, however the text you specify in the <Link> element becomes the actual name of the embedded resource.  If these two aren't consistent, it'll definitely lead to confusion. Assembly.GetManifestResourceStream is case-sensitive and won't return what you expect unless you get the case right!