FirefoxPortable + Google Gears + Google Calendar

I try to use Google Caendar offline, instaling Google Gears on FirefoxPortable
(this way https://portableapps.com/node/7364) and Gears is instaled good.

When I login to Calendar I can't use Gears (can't add Calendar site to Gears).

What am I doing wrong?

Help me, please.

P.S.I try FF 2 & 3, clear and with other addons.