When you try to import a package from the admin interface you get a Fatal Error with the following message :

Fatal error: Call to a member function getInstallState() on a non-object in .....

The problem is that the extraction process creates a zero byte package.xml file and when the system tries to open it, it of course crashes. Would it be an issue with ezcArchive ?

Steps to reproduce

Try to import a package and see the Fatal Error