ARGH Eclipse is SO frustrating

I have a directory called c:\RemoteSrc . Under this there are 3 directories which are currently source folders (I think? the icon is an open folder with a little orange grid in it) in my Eclipse project. I have dropped a new directory under c:\RemoteSrc which I also want to add to my project.

BUT

If I right click on my project and go "Build Path..." -> "Link Source" and try to add it it tells me "Folder already exists with a different case". Yes i KNOW that the folder already exists THATS WHY IM TRYING TO ADD IT.