I tried updating a Squeak 4.5 image with the default squeak45 update stream
(http://source.squeak.org/squeak45). The update fails and locks up the image,
not a good impression for new users.

The cause appears to be a corrupt copy of one of the MCZs in squeak45:

-rw-r--r--  1 squeaksource squeaksource  72368 Feb  4  2014 squeak45/System-dtl.665.mcz
-rw-r--r--  1 squeaksource squeaksource 903249 Jan 30  2014 trunk/System-dtl.665.mcz

The one in squeak45 is empty when viewed in a Monticello browser. The one
in trunk if fine.

Presumably this was some sort of error introduced in copying the MCZ from
trunk to squeak45.

I will fix this by copying the good MCZ from trunk to squeak45 using a
Monticello browser.

Dave