We attempted to install an updated version of the skin we're using on our site, but something went wrong and now when we log in we get the following error message:

An error has occurred. DotNetNuke.Services.Exceptions.ModuleLoadException: Couldn't load menu style 'admin/Menus/DNNAdmin': System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Web.DDRMenu.DNNCommon.DNNContext.get_ModuleFolder() at DotNetNuke.Web.DDRMenu.DNNCommon.PathResolver.Resolve(String path, RelativeTo[] roots) at DotNetNuke.Web.DDRMenu.MenuBase.Instantiate(String menuStyle) ---> System.ApplicationException: Couldn't load menu style 'admin/Menus/DNNAdmin': System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Web.DDRMenu.DNNCommon.DNNContext.get_ModuleFolder() at DotNetNuke.Web.DDRMenu.DNNCommon.PathResolver.Resolve(String path, RelativeTo[] roots) at DotNetNuke.Web.DDRMenu.MenuBase.Instantiate(String menuStyle) at DotNetNuke.Web.DDRMenu.MenuBase.Instantiate(String menuStyle) at DotNetNuke.Web.DDRMenu.SkinObject.OnPreRender(EventArgs e) --- End of inner exception stack trace ---

I'm not sure why the admin menu won't load. I've done a little googling but haven't had any luck. The skin we are using does include DDRmenu, which made me wonder if disabling that extension would solve the problem (as per http://markxa.com/2011/07/19/ddrmenu-2-0-and-dotnetnuke-6-0/), but the extensions.ascx page won't load. I believe we're using version 8 of DNN.

Is there another possible cause for this problem? We can't get to any admin pages and none will load when we manually enter the url.