I'm getting this with the gallery module as well, running win server 2003.

DNN installed fine, I've installed Gallery modules, then clicked the menu and add file.

Server Error in '/' Application.

---

The resource cannot be found.

The Account Login module also throws this error.

====
Server Error in '/' Application.
--------------------------------------------------------------------------------

The resource cannot be found.
Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable.  Please review the following URL and make sure that it is spelled correctly.

Requested URL: /SSO/UserAccount/tabid/4625/returnurl/ /Default.aspx
====

URL looks like  this:   "[omitted part of url]/returnurl/%20/Default.aspx" .

Just upgraded to DNN 4.7 from DNN 4.4.1.

Any ideas?

Thanks.
Ryan

didn't work for me