[plt-scheme] r6rs collection

I've been trying to experiment with the r6rs collection, but I'm
having trouble writing a working example of a r6rs library.

I have in collects/r6rs/foo.ss:

#reader(lib "library.ss" "r6rs")
(library "foo" "scheme://r6rs"
  (import)
  (export)
  1)

But then when I require (lib "foo.ss" "r6rs"), I get:

   unknown module: |,/Applications/plt/collects/r6rs/bar|

Any ideas on what I am doing wrong?

Thanks,
David