Thanks for your report, sboydman.
The installation did not ask for reboot, because it should not usually (*) need it. It seems that something was going wrong in your case.
We would appreciate if you can provide us some more information, so we can look closer at the problem:
(1) Was it a clean install, or update from older version? If an update, have you an idea what was the version installed previously?
(2) Please look at system logs if there is something what would indicate a problem cause (/var/log/system.log, /var/log/kernel.log) or provide us those logs.
(3) During the avast! beta stage, whenever something interesting happens (a main GUI starts, installation/uninstallation/upddate is performed etc.), the avast! writes a file /tmp/script.log-[NUMBER] so we can see what happens. We are very interested in those files from time when the problem occurs. However /tmp is deleted during reboot so you probably do not have the relevant files there anymore. However it would be very helpful if you try to reproduce the problem. If it issue happens again, collect those files (use file creation date/time to pick the ones from the reinstall time) and provide them.
Regards,
Mity
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Footnotes:
(*) Actually in exceptional cases it may need the reboot when updating from older beta build, and some KExt of old version refuses to unload which may happen. But then the GUI should ask you to perform the reboot, and we believe this can only happen on 10.5.x and 10.6.x, and not 10.7.x.