[racket] Error generating scribble docs by PLaneT packager

I'm trying to create a planet archive and am getting the error below.
Any ideas on what might be wrong? Thanks,
--- nadeem


$ raco planet create /...path.../racketui/

Building: scribblings/racketui.scrbl
PLaneT packager: Error generating scribble documentation:
declare-exporting: not a module path at: (planet #f) in:
(declare-exporting (planet #f) #:use-sources ())

 === context ===
/Applications/Racket/collects/scribble/private/manual-mod.rkt:144:0
try-next
/Applications/Racket/collects/racket/private/modbeg.rkt:46:4
standard-module-name-resolver
/Applications/Racket/collects/planet/util.rkt:271:0: render
/Applications/Racket/collects/planet/util.rkt:349:2: make-planet-archive
/Applications/Racket/collects/planet/raco.rkt: [running body]
/Applications/Racket/collects/raco/raco.rkt: [running body]
/Applications/Racket/collects/raco/main.rkt: [running body]


Refusing to continue packaging.