this can be easily bypassed...
The autoupdate will direct you to the download page.
You can do it yourself by going here (for ZAAS):
Download the latest version and save it on the desktop.
Given that your ZAAS has already some problems. The best is to:
1. On your current ZA, Uncheck "load ZA.. at startup" (ZA overview --> preferences tab)
3. Install the update and then when asked choose "clean install" (to start with a fresh ZA install)