RCommander freezes immediately

Binary package hint: r-cran-rcmdr

### Ubuntu Version ###

lsb_release -rd
Description: Ubuntu 11.04
Release: 11.04

### Package Version ###

apt-cache policy r-cran-rcmdr
r-cran-rcmdr:
  Installed: 1.6-2-1
  Candidate: 1.6-2-1
  Version table:
 *** 1.6-2-1 0
        500 http://archive.ubuntu.com/ubuntu/ natty/universe i386 Packages
        100 /var/lib/dpkg/status

### What I expected to happen ###

I expected R Commander to work without freezing.

### What happened instead ###

The R Commander window appears, but doesn't respond to mouse input. If it's minimized and restored, the window contents are blanked, as if they aren't being redrawn.

Here's the console output:

$ r --interactive
library(Rcmdr)
Loading required package: tcltk
Loading Tcl/Tk interface ... done
Loading required package: grDevices
Loading required package: utils
Loading required package: car
Loading required package: stats
Loading required package: graphics
Loading required package: MASS
Loading required package: nnet
Loading required package: survival
Loading required package: splines

Rcmdr Version 1.6-2

Attaching package: 'Rcmdr'

The following object(s) are masked from 'package:tcltk':

    tclvalue