[plt-scheme] v4 webserver/packaging bug?

hello,

i tried to upgrade to the v4 web server, and ran into the following problem:

/usr/local/bin/plt-web-server -p 8181 -f configuration-table
"../web-config-unit.ss" broke the contract 
  (->
   path-string?
   #:listen-ip
   (or/c false/c string?)
   #:make-servlet-namespace
   (->*
    ()
    (#:additional-specs (listof any/c))
    namespace?)
   #:port
   (or/c false/c number?)
   unit?)
on configuration-table->web-config@; expected a procedure that accepts 1 ordinary argument and 
the mandatory keywords #:listen-ip #:make-servlet-namespace #:port, given: 
#<procedure:configuration-table->web-config@>

 === context ===
/usr/local/mz-3.99.0.12/collects/scheme/private/contract-guts.ss:200:0: raise-contract-error


this is with:
http://pre.plt-scheme.org/installers/mz-3.99.0.12-bin-i386-linux-ubuntu.sh
on debian/etch

however, using this:
http://pre.plt-scheme.org/installers/plt-3.99.0.12-bin-i386-linux-ubuntu.sh

doesn't trigger the error.

groet,
tom