package mzscheme 2:4.0.1+fake.2 failed to install/upgrade: upgrade to karmic

[lawnsea]

Binary package hint: drscheme

mzscheme failed to upgrade when moving to karmic.

ProblemType: Package
Architecture: amd64
Date: Tue Nov 24 18:59:08 2009
Dependencies:

DistroRelease: Ubuntu 9.10
ErrorMessage:
 ErrorMessage: subprocess installed post-removal script returned error exit status 1
NonfreeKernelModules: nvidia
Package: mzscheme 2:4.0.1+fake.2
PackageArchitecture: all
ProcVersionSignature: Ubuntu 2.6.31-15.50-generic
SourcePackage: drscheme
Title: package mzscheme 2:4.0.1+fake.2 failed to install/upgrade:
Uname: Linux 2.6.31-15-generic x86_64

[lawnsea (lawnsea)]

Here's the output from a recent run of apt-get:
Removing mzscheme ...
rmdir: failed to remove `/usr/local/lib/plt': Not a directory
dpkg: error processing mzscheme (--remove):
 subprocess installed post-removal script returned error exit status 1
Errors were encountered while processing:
 mzscheme
E: Sub-process /usr/bin/dpkg returned an error code (1)