Comment 7 for bug 1124149

The source of the bug is qdbus (4:4.8.4+dfsg-0ubuntu9). The binary file was moved from /usr/bin/qdbus to /usr/lib/i386-linux-gnu/qt4/bin/qdbus. So it is not in root's PATH and can't be run in powerbtn.sh:46.
There are TEMPORARY solutions for users:
1) Install http://packages.ubuntu.com/quantal/qdbus and hold it.
2) Create symlink from /usr/bin/qdbus pointing to /usr/lib/i386-linux-gnu/qt4/bin/qdbus.
3) Patch /etc/acpi/powerbtn.sh:
diff --git a/acpi/powerbtn.sh b/acpi/powerbtn.sh
--- a/acpi/powerbtn.sh
+++ b/acpi/powerbtn.sh
@@ -43,7 +43,7 @@ elif test "$XUSER" != "" && test -x /usr/bin/qdbus; then
         kded4pid=$(pgrep -n -u $XUSER kded4)
         if test "$kded4pid" != ""; then
                 dbusaddr=$(su - $XUSER -c "grep -z DBUS_SESSION_BUS_ADDRESS /proc/$kded4pid/environ")
- if test "$dbusaddr" != "" && su - $XUSER -c "export $dbusaddr; qdbus org.kde.kded" | grep -q powerdevil; then
+ if test "$dbusaddr" != "" && su - $XUSER -c "export $dbusaddr; /usr/lib/i386-linux-gnu/qt4/bin/qdbus org.kde.kded" | grep -q powerdevil; then
                         exit
                 fi
         fi

I don't know whom to ask to fix this bug. So please tell the right person to fix it, because it's a release blocking bug I think.