Or use the google authenticator app on an offline computer.
the clock on an offline computer will vary over time, which will make your otp give a bad result. update the time manually if the otp is gives doesn't work.
I tried to set 2fa on mtgox use this method via offlline computer (mini winxp on hirens boot usb) and get wrong otp. I had set time and date same in second and get different otps. Online (same comp as mtgox session) generated otp well matched.
any advice, what is going wrong? thanks in advance!
This is most likely the clock creep issue. The OTP only lasts for 30 seconds, so if the clock is wrong it will not be calculated for the correct time as observed by Mt. Gox. The best solution is to use a system connected to a time (NTP) server, otherwise you'll have to update the clock manually.