Comment 0 for bug 828287

$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
  pcmanfm
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be REMOVED:
  libfm-gtk0 lubuntu-core lubuntu-default-settings lxde-core pcmanfm
0 upgraded, 0 newly installed, 5 to remove and 0 not upgraded.
After this operation, 2,019 kB disk space will be freed.

$ sudo apt-get install pcmanfm
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  libfm-data libfm-gtk-data libfm-gtk1 libfm1
The following packages will be REMOVED:
  libfm-gtk0 libfm0
The following NEW packages will be installed:
  libfm-data libfm-gtk-data libfm-gtk1 libfm1
The following packages will be upgraded:
  pcmanfm
1 upgraded, 4 newly installed, 2 to remove and 0 not upgraded.
Need to get 560 kB of archives.
After this operation, 295 kB of additional disk space will be used.

The only thing I can see is that apt-cache says libfm-data depends on libfm0, whereas dpkg says that it replaces and conflicts with it:

$ apt-cache showpkg libfm-data
Package: libfm-data
Versions:
0.1.16-0ubuntu1 (/var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_oneiric_universe_binary-i386_Packages) (/var/lib/dpkg/status)
 Description Language:
                 File: /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_oneiric_universe_binary-i386_Packages
                  MD5: b68a3e57e44d0a8e239e9ab01d4c5180

Reverse Depends:
  libfm1,libfm-data
Dependencies:
0.1.16-0ubuntu1 - libfm0 (0 (null)) libfm0 (0 (null))
Provides:
0.1.16-0ubuntu1 -
Reverse Provides:

$ dpkg -s libfm-data
Package: libfm-data
Status: install ok installed
Priority: extra
Section: libs
Installed-Size: 1248
Maintainer: Ubuntu Developers <email address hidden>
Architecture: all
Source: libfm
Version: 0.1.16-0ubuntu1
Replaces: libfm0
Conflicts: libfm0
Conffiles:
 /etc/xdg/libfm/libfm.conf 428d3e51fff8ead6d0f1b2cae0884e22
Description: file management support - common files
 LibFM provides file management functions built on top of Glib/GIO,
 giving a convenient higher-level API. Features:
  * Desktop-independent, following FreeDesktop standards;
  * Fast, light on memory usage, and responsive - well suited to
    less powerful hardware such as netbooks and thin clients;
  * Uses GIO/GVFS (like Nautilus) for Trash support and access to
    remote file systems (FTP, SFTP, WebDAV, Windows shares, etc.);
  * Clipboard operations are compatible with GTK+/GNOME and Qt/KDE;
  * Supports both Drag-and-Drop, and the X Direct Save protocol;
  * Reusable design with the core functions separated out to
    simplify porting to other GUIs.
 .
 This package contains common files of libfm library.
Homepage: http://pcmanfm.sourceforge.net/
Original-Maintainer: Debian LXDE Packaging Team <email address hidden>

The workaround to get PCmanFM 0.9.9 to install correctly is to manually install it with "sudo apt-get install pcmanfm".

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: pcmanfm 0.9.9-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-8.11-generic 3.0.1
Uname: Linux 3.0.0-8-generic i686
Architecture: i386
Date: Wed Aug 17 14:57:58 2011
InstallationMedia: Lubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110801)
Pref_Config_System_lubuntu:
 [Preferred Applications]
 WebBrowser=firefox.desktop
 MailClient=
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: pcmanfm
UpgradeStatus: No upgrade log present (probably fresh install)