I believe I have the same problem described here:
indexhibit.org/forum/thread/22303/
In the upper right corner I have Preferences / Help / Logout, but not Admin. I tried replacing the index.php file that you suggested in the above link, but I assume it never runs because I still can't see the admin link.
My site is anikasteppe.com and I am running Indexhibit v2.
Please advise.