Update Manager fails to install updates, clicking "Install Updates" button has no effect

[msp3k]

Binary package hint: yelp

Sometimes when updates are available, the Update Manager window will appear. Sometimes, clicking "Install Updates" will have no effect. This only seems to happen when the Update Manager window appears on it's own. If I select System > Administration > Update Manager, then the "Install Updates" button will work just fine. (I've had this problem with my 9.04 installation too, but not with 8.10.)

ProblemType: Bug
Architecture: amd64
Date: Thu Nov 12 08:26:30 2009
DistroRelease: Ubuntu 9.10
ExecutablePath: /usr/bin/yelp
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
NonfreeKernelModules: wl fglrx
Package: yelp 2.28.0-0ubuntu2
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-14.48-generic
SourcePackage: yelp
Uname: Linux 2.6.31-14-generic x86_64

[msp3k (peek-nimbios)]

This happened on a second Ubuntu machine (this second one is running in VirtualBox on an OSX machine).

I have an strace log to contribute, it it's helpful. The strace command line was:

strace -f -F -tt -x -e trace=all -e signal=all -e read=all -e write=all -o ~/Desktop/update-manager-strace.txt -p 1848

The point where I click "Install Updates" button happens at 08:43:10.464345