Error (ERROR_REQUEST_FORGED)in modules/core/classes/.... -> main.php

Gallery version (not just "2.3"):2.3
PHP version (e.g. 5.2.8):5.2.8
PHPInfo Link (see FAQ):
Webserver (e.g. Apache 1.3.33):1.3.41
Database (e.g. MySql 5.0.32):5.0.77
Activated toolkits (e.g. NetPbm, GD):Image Magick, GD, FFMPEG
Operating system (e.g. Linux):Linux
Browser (e.g. Firefox 2.0):IE8 & Firefox

Gallery Error
Location : http://../gallery/main.php
ERROR_REQUEST_FORGED

Error (ERROR_REQUEST_FORGED)in modules
/core/classes/GalleryController.class at line 239 (GalleryCoreApi::error) in main.php at line 243
(GalleryController::assertIsGenuineRequest) in main.php at line 104 in main.php at line 88 Request variables: Array ( [return] => /gal/gallery/main.php [formUrl] => /gal/gallery/main.php?g2_view=core.UserAdmin&g2_subView=core.UserLogin [authToken] => 923a24f8fcb7 [controller] => core.UserLogin [form] => Array ( [formName] => UserLogin [username] => giorgio [password] => xxx [action] => Array ( [login] => Login ) ) )

Can you help me ??

Thank you