Relevant part of the log: * Installing 1 assembly from libdbus1.0-cil into Mono ** (/usr/lib/mono/2.0/gacutil.exe:17198): WARNING **: The following assembly referenced from /usr/lib/mono/2.0/gacutil.exe could not be loaded: Assembly: Mono.Security (assemblyref_index=1) Version: 2.0.0.0 Public Key: 0738eb9f132ed756 The assembly was not found in the Global Assembly Cache, a path listed in the MONO_PATH environment variable, or in the location of the executing assembly (/usr/lib/mono/2.0/). ** (/usr/lib/mono/2.0/gacutil.exe:17198): WARNING **: Could not load file or assembly 'Mono.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756' or one of its dependencies. Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'Mono.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756' or one of its dependencies. File name: 'Mono.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756' at Mono.Tools.Driver.LoadConfig (Boolean quiet) [0x00000] in :0 at Mono.Tools.Driver.Main (System.String[] args) [0x00000] in :0 E: installing Assembly /usr/lib/cli/dbus-sharp-1.0/dbus-sharp.dll failed E: Installation of libdbus1.0-cil with /usr/share/cli-common/runtimes.d/mono failed dpkg: error processing libdbus1.0-cil (--configure): subprocess installed post-installation script returned error exit status 9 dpkg: dependency problems prevent configuration of gnome-do-plugins: gnome-do-plugins depends on libdbus1.0-cil (>= 0.7); however: Package libdbus1.0-cil is not configured yet. dpkg: error processing gnome-do-plugins (--configure): dependency problems - leaving unconfigured Setting up libappindicator0.1-cil (0.2.96-0ubuntu1) ... * Installing 3 assemblies from libappindicator0.1-cil into Mono ** (/usr/lib/mono/2.0/gacutil.exe:17210): WARNING **: The following assembly referenced from /usr/lib/mono/2.0/gacutil.exe could not be loaded: Assembly: Mono.Security (assemblyref_index=1) Version: 2.0.0.0 Public Key: 0738eb9f132ed756 The assembly was not found in the Global Assembly Cache, a path listed in the MONO_PATH environment variable, or in the location of the executing assembly (/usr/lib/mono/2.0/). ** (/usr/lib/mono/2.0/gacutil.exe:17210): WARNING **: Could not load file or assembly 'Mono.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756' or one of its dependencies. Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'Mono.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756' or one of its dependencies. File name: 'Mono.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756' at Mono.Tools.Driver.LoadConfig (Boolean quiet) [0x00000] in :0 at Mono.Tools.Driver.Main (System.String[] args) [0x00000] in :0 E: installing Assembly /usr/lib/cli/appindicator-sharp-0.1/appindicator-sharp.dll failed E: Installation of libappindicator0.1-cil with /usr/share/cli-common/runtimes.d/mono failed dpkg: error processing libappindicator0.1-cil (--configure): subprocess installed post-installation script returned error exit status 9