[wp-testers] Plugin Installer and Updater no longer working after last night's build

[beanz]

All plugin installs and upgrades are now stalling at the unpacking stage
after updating to last nights build.
It worked fine yesterday and it works on all of the blogs running 2.9.2 on
the same server.
I have tried it on 6 different plugins and it stalls on everyone of them but
they can all be successfully installed/upgraded on other blogs on that
server.