Mijik offered this fix for IIS problems on our sister site WPVerse.com, we haven’t tested it yet as we’re all Linux based here…
Fix for displaying the options page in WP 3.1 and to fix crashing on Microsoft IIS web servers:
edit functions.php, line 305, replace:
add_theme_page('P2 Reloaded Options', 'P2 Reloaded Options', 8, __FILE__, 'prologue_options_page');
with:
add_theme_page('P2 Reloaded Options', 'P2 Reloaded Options', 'edit_theme_options', 'p2-options-page', 'prologue_options_page');.
More info here: http://core.trac.wordpress.org/ticket/10011