I just noticed something today.  If you put a Text/HTML module on a page, and that page is configured to link to another page, then if you try to edit the settings of that Text/HTML module, you get this "Error: Module is currently unavailable." msg (Full error text at bottom of this post). 

So why am I putting a text/html module on a page that is linking to another page?  I doing it for Search purposes.  I have an ASP file that displays all files from a specific folder in an IFrame module on one Master IFrame page.  I use a pass-through querystring parameter to display the files from the appropriate folder.  So every lowest-level page links to this Master page, passing thru the appropriate querystring param.   So I'm using Text/HTML modules on each page that links to this Master IFrame page so that they show up in searches.  But I don't know why that should matter or generate this error. Just thought I'd report it.

Error: Module is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Modules.Admin.Modules.ModuleSettingsPage.BindData() at DotNetNuke.Modules.Admin.Modules.ModuleSettingsPage.Page_Load(Object sender, EventArgs e) --- End of inner exception stack trace ---