Problem is caused by a cookie. Quick fix is to park a different subdomain on top of your OpenX domain and use that subdomain to access admin.
Last week I installed OpenX on my server to use for an upcoming project. After getting it installed and setup admin-side, I went and made sure the zones looked right on the project site. Chrome gave me an error that it was in a redirect loop.
It appears this is a very common problem with forum threads all around. The cause is that OpenX uses the same cookie name for both ad viewer tracking and admin logins, a cookie named OAID. Since OpenX is open source I could have dug through the code and either figured out why it was redirecting or changed the cookie name. But I wasn’t really up to that.
Closest thing I found online to a solution was to either clear cookies between using the admin side and checking the production site, or to use two different browsers. Neither a really good solution.
Came up with a better, and much easier, solution.