Dragging a launcher icon to Docky results in crash

Dragging a launcher icon from a Gnome panel onto Docky often results in a crash. Running docky --debug produces the following:

docky --debug
[Info 12:12:47.661] Docky version: 2.0.5 Release
[Info 12:12:47.674] Kernel version: 2.6.32.24
[Info 12:12:47.675] CLR version: 2.0.50727.1433
[Debug 12:12:47.891] [UserArgs] BufferTime = 0
[Debug 12:12:47.892] [UserArgs] MaxSize = 2147483647
[Debug 12:12:47.892] [UserArgs] NetbookMode = False
[Debug 12:12:47.892] [UserArgs] NoPollCursor = False
[Info 12:12:47.948] [DockController] Setting theme: HUD
[Info 12:12:48.200] [PluginManager] Loaded "Docky.Widgets,1.0".
[Info 12:12:48.200] [PluginManager] Loaded "Docky.Widgets,1.0".
[Info 12:12:48.201] [PluginManager] Loaded "Clock".
[Info 12:12:48.204] [PluginManager] Loaded "CPU Monitor".
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/banshee_control.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/deluge_badge.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/gajim_badge.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/gtg_menus.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/liferea_badge.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/open_terminal_here.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/pidgin_control.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/rhythmbox_control.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/tomboy_menus.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/zeitgeist_docky.py
[Info 12:12:49.880] [HelperService] Helper added: /usr/share/docky/helpers/zeitgeist_journal.py
[Info 12:12:49.885] [DrawingService] Could not find 'banshee', using fallback of 'extension'.
[Info 12:12:49.891] [DrawingService] Could not find 'deluge', using fallback of 'extension'.
[Info 12:12:49.896] [DrawingService] Could not find 'gajim', using fallback of 'extension'.
[Info 12:12:49.901] [DrawingService] Could not find 'gtg', using fallback of 'extension'.
[Info 12:12:49.924] [DrawingService] Could not find 'pidgin', using fallback of 'extension'.
The program 'Docky' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 261312 error_code 3 request_code 3 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

Found on:
Ubuntu 10.04 64 bit
Docky 2.05
X 11
ATI Radeon HD 4500
Gnome 2.30.2
I don't know Mono, how do I find this out?