What must I do to get this?

I am a member of five years ago, but it shows only the 4 year longtime member achievment as done. T_T

At the top, under the "personal"tab, click on site preferences.

go to Personal and than Site Preferences. here (i am not sure if the links works by you, becasue its mine ;) )

hope that helps

EDITH: argh... i am sooo slow

Thanks. ^o^ It works.