addlocale will clean your rpm-cache before downloading the needed packages. This is needed to get this fancy progress dialog window working

4.0-6 works fine here using PASS, KDE, and British English.
Try running it again, maybe there was some network timeout.
Or you can try to edit as root /usr/bin/addlocale and at line
a) 1852 change
sleep 1 to
sleep 2b) 1862 enter
sleep 5, then save the file and run addlocale with this and let me know if this helped.
I will only have time tomorrow to look into this any further.
-p.