Install went without a hitch.
On launching Firefox, I get a bright red bar across the top with this:
The bookmarks and history system will not be functional because on of Firefox's files is in use by another application. Some security software can cause this problem.
This persists after reboot.
When I run the original system FF 3.0 manually, it doesn't even give me the error... but has nothing in the bookmarks toolbar and it doesn't appear to be loading any profile at all.
I've tried to restore previous bookmark backups that I have and it errors out.
Any ideas?