Limewire wont recognise my files!

I try to add files for sharing by putting copies in the Shared folder, But when I do, most of them don't appear to exist in the Limewire Library.

Why isn't limewire recognising the files I put in the Shared Folder?? Is it somthing to do with filename extensions, Because the only files it seems to recognise are those with visible extensions.

As I dont know how to add an appropiate extension to a file, this is becoming very frustrating...

Any assistance would be most appreciated.