I have a site that had been functioning for some time. Its an anonymous access site. Now however, when I try to login I get an error:

/Default.aspx?tabid=36&error=Object+reference+not+set+to+an+instance+of+an+object.

Oddly enough this error only occurs in IE! In firefox things seem to be OK, other than icons on the admin pages do not appear.  Any thoughts?

mikemog:

Did you ever resolve this (Login Error): Object reference not set to an instance of an object

I'm getting the same error after an upgrade from 4.0.3 to 4.3.0 - right at login time - and for me it a little more serious: I cannot login at all.

I spent weeks looking for a solution... but never found one.  I rolled back to 4.0.3 and stayed there until that particular portal (used in a biz environment for a project) was not longer needed.  I later installed a clean 4.3.2 installation that works great.  But so far as upgrading from 4.0.x - I kept getting the "object reference..." error and never resolved it.

I was at the point where I consider trying to "Transfer Objects" from my working DNN 4.0.3 installation to a clean working DNN 4.3.x installation, but I never "had" to do it because the portal need expired.  I was going to use Vale Software's MSDE Manager to do that MS SQL Server database Transfer (All) Objects, just in case that helps you toward a solution.  I heard of another person solving a similar problem by Transfering (All) Objects from one working DNN installation to another working installation.  But I've yet to try an Objects Transfer, so I'm not sure how easy/hard/useful that process might be...