I forgot to mention, I tried this from both Firefox 9.0.1 and Safari 5.1.2. Same issue on both, going to any option page results in a login form, logging in will work, changing an option and saving results in another login form, and after logging in redirects back to the main admin site with the ""saveoptions" Cross Site Request Forgery blocked." error message...
--Edit--
Also, my security log shows this, if its any help.

(Usernames/IP masked, everything else untouched.)
2012-01-14 12:58:04 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:00:56 72.29.*.* Blocked access Failed /zp-core/admin-options.php?action=saveoptions
2012-01-14 13:00:58 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:00:59 72.29.*.* XSRF access blocked usrname Name Failed saveoptions
2012-01-14 13:09:25 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:17:27 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:17:31 72.29.*.* Blocked access Failed /zp-core/admin-options.php?page=options&tab=general
2012-01-14 13:17:37 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:17:44 72.29.*.* Blocked access Failed /zp-core/admin-options.php?action=saveoptions
2012-01-14 13:19:11 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:19:16 72.29.*.* Blocked access Failed /zp-core/admin-options.php?page=options&tab=general
2012-01-14 13:19:25 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:19:30 72.29.*.* Blocked access Failed /zp-core/admin-options.php?action=saveoptions
2012-01-14 13:19:36 72.29.*.* Admin login usrname Name Success zp_admin
2012-01-14 13:19:37 72.29.*.* XSRF access blocked usrname Name Failed saveoptions