I have problem too… 10.5.5 9F33 intel Safari 3.1.2 After install i see menu Google gears, but when i go to reader or google docs nothing happens…
In /Library/InputManagers/GearsEnabler In Internet Plug-Ins/Gears.plugin In Users/Me/Library/ i don't have folder InputManagers and in Internet Plug-Ins i don't have gears too. Gears version 0.4.22.0
