Wrong redirection to 404 page after logging as Admin

[luigiusai]

Hi,

I am Luigi Usai, from Verona, Italy.
I did a backup copy of my Joomla website - www.iperstoria.it;
(Joomla! 2.5.4 Stable [ Ember ] 2-April-2012 14:00 GMT)
I installed the MySql database;
Run the website: everything's ok! The website works.
I log in as Administrator: interface is ok!
I set login name and password and then click ok:

ERROR: Joomla! redirects me to page 404. This is a wrong behavior.

So I go to configuration.php:

1) public $debug = '1';
2) I start again the procedure until I land to the Admin Login Page;
3) I put login and password, and I click ok;
4) this is the result of the debugger:

Console Debug Joomla!
Errori (it means errors)
Sessione
Informazioni profilo
Utilizzo memoria
Queries Database

I open the menu Errori and I see this:

Errori

Componente non trovato
Call stack
# Function Location
1 JSite->dispatch() JROOT\index.php:42
2 JComponentHelper::renderComponent() JROOT\includes\application.php:198
3 JError::raiseError() JROOT\libraries\joomla\application\component\helper.php:355
4 JError::raise() JROOT\libraries\joomla\error\error.php:251

Problem: this kind of error prevents me from loggin as Administrator in my Localhost (127.0.0.1) backup copy of Joomla!

Some of you does understand how to solve this?
Thank you very much in advance.

Luigi Usai, Verona, Italy

[luigiusai]

I asked Mark please taking a look at this bug, maybe we can solve it quickly:
https://github.com/dextercowley

[luigiusai]

What I did:

I had a component which wasn't working, so I disabled it with PHP My Admin;
I set enabled = 0; // to the component, a JResearch tool;

What I think is happening:

maybe I should disable this component on the Admin site; maybe it's for this that redirection is wrong, but I only guess... Any help welcome. Thank you in advance.