childsplay doesn't start the first of the two numbers plugins

Binary package hint: childsplay

There are two plugins that does not start in childsplay. Here is the output of childsplay in a terminal:
[..]
$ childsplay --window

     Copyright (C) 2002-2006 Stas Z. <email address hidden>

 This program is free software; you can redistribute it and/or
 modify it under the terms of version 2 of the GNU General Public License
 as published by the Free Software Foundation. A copy of this license should
 be included in the file GPL-2.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; see the file GPL-2. If not, write to
 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

 Childsplay - A suite of educational games for young children.

  This is beta software, please send bugs and/or comments to
  <email address hidden>
Setting childsplay locale to 'de_DE.UTF-8@euro'
stop_splash called
  Numbers.py - part of childsplay.py, a suite of educational games for
  young children.

  When the balloons pop get a operator with the left button. Put it at
  the questionmark and hit the left button again.
  That's all for now.
************************************************************
Traceback (most recent call last):
  File "/usr/share/childsplay/childsplay.py", line 988, in main
    game.start(l,i)
  File "/usr/share/childsplay/lib/numbers.py", line 192, in start
    s = pygame.Surface(r[-2:])
TypeError: argument 1 must be sequence of length 2, not 1
 Please send a bug report with this stuff to,
 <email address hidden>
************************************************************
********************** ERROR *********************
 A error occured in module None LineNo: None
 Info: None
 The original error message is:
argument 1 must be sequence of length 2, not 1
**************************************************
[..]

All other plugins are working well.