[plt-scheme] PLT installer doesn't work

Hello all,

I've just got the pre-release installer for Ubuntu.
Installing in Ubuntu 7.10:
pmatos at leibniz:~/Desktop$ sh full-3.99.0.20-bin-i386-linux-ubuntu.sh
This program will extract and install PLT Scheme Full v3.99.0.20.

Note: the required diskspace for this installation is about 206M.

Do you want a Unix-style distribution?
  In this distribution mode files go into different directories according
  to Unix conventions.  A "plt-uninstall" script will be generated to
  make it possible to remove the installation.  If say 'no', the whole
  PLT directory is kept as a single (movable and erasbale) unit, possibly
  with external links into it.
*** This is a nightly build: such a distribution is not recommended
*** because it cannot be used to install multiple versions.
Enter yes/no (default: no) > yes

Where do you want to base your installation of PLT Scheme Full v3.99.0.20?
  (Use an existing directory.  If you've done such an installation in
   the past, either use the same place, or manually run
   'plt-uninstaller' now.)
  1 - /usr/... [default]
  2 - /usr/local/...
  3 - $HOME/... (/home/pmatos/...)
  4 - ./... (here)
  Or enter a different directory prefix to install in.
> Error: Aborting...
pmatos at leibniz:~/Desktop$ sudo sh full-3.99.0.20-bin-i386-linux-ubuntu.sh
[sudo] password for pmatos:
This program will extract and install PLT Scheme Full v3.99.0.20.

Note: the required diskspace for this installation is about 206M.

Do you want a Unix-style distribution?
  In this distribution mode files go into different directories according
  to Unix conventions.  A "plt-uninstall" script will be generated to
  make it possible to remove the installation.  If say 'no', the whole
  PLT directory is kept as a single (movable and erasbale) unit, possibly
  with external links into it.
*** This is a nightly build: such a distribution is not recommended
*** because it cannot be used to install multiple versions.
Enter yes/no (default: no) > yes

Where do you want to base your installation of PLT Scheme Full v3.99.0.20?
  (Use an existing directory.  If you've done such an installation in
   the past, either use the same place, or manually run
   'plt-uninstaller' now.)
  1 - /usr/... [default]
  2 - /usr/local/...
  3 - $HOME/... (/home/pmatos/...)
  4 - ./... (here)
  Or enter a different directory prefix to install in.
> 1

Target Directories:
  [e] Executables   /usr/bin (exists)
  [s] Scheme Code   /usr/lib/plt/collects (will be created)
  [d] Core Docs     /usr/share/plt/doc (will be created)
  [l] C Libraries   /usr/lib (exists)
  [h] C headers     /usr/include/plt (will be created)
  [o] Extra C Objs  /usr/lib/plt (will be created)
  [m] Man Pages     /usr/man (will be created)
  (C sources are not kept)
Enter a new prefix, a letter to change an entry, enter to continue
>

Checking the integrity of the binary archive... ok.
Unpacking into "/usr/full-3.99.0.20-tmp-install"... done.
Moving bin -> /usr/bin
Moving collects -> /usr/lib/plt/collects
Moving doc -> /usr/share/plt/doc
Moving include -> /usr/include/plt
Moving lib -> /usr/lib/plt
Moving man -> /usr/man
Moving readme.txt -> /usr/share/plt/doc/readme.txt
*** Error: undoing changes...
procedure open-input-output-file: expects 1 argument plus optional
arguments with keywords #:exists and #:mode, given 2:
"mred-temp-for-install" update

 === context ===
/usr/full-3.99.0.20-tmp-install/collects/setup/unixstyle-install.ss:154:4:
fix-binary
/usr/full-3.99.0.20-tmp-install/collects/setup/unixstyle-install.ss:368:2:
move/copy-distribution

Error: installation failed
  (Removing installation files in /usr/full-3.99.0.20-tmp-install)

Cheers,

-- 
Paulo Jorge Matos - pocm at soton.ac.uk
http://www.personal.soton.ac.uk/pocm
PhD Student @ ECS
University of Southampton, UK
Sponsor ECS runners - Action against Hunger:
http://www.justgiving.com/ecsrunslikethewind