Uploading theme give AJAX error

I just installed 7.0-rc1 and began working on a new site. At this point, I have a single piece of content (an article) created, but not published.

I went to upload a new theme. I clicked on the "Appearance" tab, then clicked "+Install new theme", then pasted the URL (http://ftp.drupal.org/files/projects/corolla-7.x-1.17.tar.gz) into the "Install from a URL" box, and clicked the Install button. This got me a page the flashed up with an AJAX error message, then after maybe 1 or 2 seconds, went away and was replaced with a page telling me the theme had been installed (or whatever; I don't remember the exact message). Navigating back with my browser's back button, I found a page with the following text on it:

An AJAX HTTP error occurred. HTTP Result Code: 200 Debugging information follows. Path: http://cityislandsoftware.com/authorize.php?batch=1&render=overlay&id=2&... StatusText: OK ResponseText: Welcome to cityislandsoftware.com | cityislandsoftware.com @import url("http://cityislandsoftware.com/modules/system/system.base.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/system/system.menus.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/system/system.messages.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/system/system.theme.css?lcz6rm"); @import url("http://cityislandsoftware.com/misc/ui/jquery.ui.core.css?lcz6rm"); @import url("http://cityislandsoftware.com/misc/ui/jquery.ui.theme.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/overlay/overlay-parent.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/contextual/contextual.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/comment/comment.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/field/theme/field.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/node/node.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/search/search.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/user/user.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/shortcut/shortcut.css?lcz6rm"); @import url("http://cityislandsoftware.com/modules/toolbar/toolbar.css?lcz6rm"); @import url("http://cityislandsoftware.com/themes/bartik/css/layout.css?lcz6rm"); @import url("http://cityislandsoftware.com/themes/bartik/css/style.css?lcz6rm"); @import url("http://cityislandsoftware.com/themes/bartik/css/colors.css?lcz6rm"); @import url("http://cityislandsoftware.com/themes/bartik/css/print.css?lcz6rm"); Skip to main content Options for the administrative overlayIf you have problems accessing administrative pages on this site, disable the overlay on your profile page. Dismiss this message. Home Hello roy Log out Administrative toolbarDashboard (View and customize your dashboard.) Content (Administer content and comments.) Structure (Administer blocks, content types, menus, etc.) Appearance (Select and configure your themes.) People (Manage user accounts, roles, and permissions.) Modules (Enable or disable modules.) Configuration (Administer settings.) Reports (View reports, updates, and errors.) Help (Reference for usage, configuration, and modules.) Hide shortcuts Add content Find content Edit shortcuts cityislandsoftware.com Main menuHome Secondary menuMy account Log out Error message No active batch. No active batch. Configure block Search form Search Navigation List links Edit menu Configure block Add content Welcome to cityislandsoftware.com No front page content has been created yet.Add new content Configure block Powered by Drupal

As far as I can tell, the theme did get installed and seems to work, so I don't know what the AJAX errors are all about.

I'm using Chrome 7.0.517.44 on OSX-10.6.5. PHP-5.2.14. MySQL 5.1 backend.