drupal settings path to tmp folder has to match the php.ini one

Hi... really this one make me crazy.

1) CCK 6.x-2.9
Drupal 6.22
FileField 6.x-3.10

3) www-data has rw to /tmp and sites/default/files and I can upload other type of file on simple filefield (like .txt).
4) public
5) see the image object down
6) click on upload button and see the thumbnail at the end of the upload
7) click... wait 0.5s and show two erro messages inside the widget:
* "The file is not a known image format"
* "The selected file %name could not be saved."

8) create a node, try to upload an image.

I'm on Debian squeez. Sudently I get "The file is not a known image format" every time I try to upload an image without apparently changing somethings...

I print_r the file object in the image inside the function filefield_validate_is_image. So in fact is "simply" than image_get_info return FALSE. After the upload they are no file in /tmp...

I check than I have fileinfo extension loaded and it is. It's installed with http://packages.debian.org/squeeze/libapache2-mod-php5

Is linked to the server configuration because on local it works with the files and database from the production.

Here the file object:

stdClass Object
(
    [filename] => screen_shot_2011-07-17_at_1.42.03_pm.png
    [filepath] => /tmp/php32093o
    [filemime] => image/png
    [source] => group_images_field_image_0
    [destination] => sites/default/files/articles-thumbnail-image/screen_shot_2011-07-17_at_1.42.03_pm.png
    [filesize] => -19
    [field] => Array
        (
            [field_name] => field_image
            [type_name] => articles
            [display_settings] => Array
                (
                    [weight] => 0
                    [parent] => group_images
                    [label] => Array
                        (
                            [format] => hidden
                        )

                    [teaser] => Array
                        (
                            [format] => image_plain
                            [exclude] => 0
                        )

                    [full] => Array
                        (
                            [format] => image_plain
                            [exclude] => 1
                        )

                    [monsite_one_col] => Array
                        (
                            [format] => thumbnail_one_col_linked
                            [exclude] => 0
                        )

                    [monsite_one_col_promoted] => Array
                        (
                            [format] => thumbnail_one_col_promoted_linked
                            [exclude] => 0
                        )

                    [monsite_two_col] => Array
                        (
                            [format] => thumbnail_two_col_linked
                            [exclude] => 0
                        )

                    [4] => Array
                        (
                            [format] => image_plain
                            [exclude] => 0
                        )

                    [2] => Array
                        (
                            [format] => image_plain
                            [exclude] => 0
                        )

                    [3] => Array
                        (
                            [format] => image_plain
                            [exclude] => 0
                        )

                    [token] => Array
                        (
                            [format] => image_plain
                            [exclude] => 0
                        )

                )

            [widget_active] => 1
            [type] => filefield
            [required] => 0
            [multiple] => 0
            [db_storage] => 0
            [module] => filefield
            [active] => 1
            [locked] => 0
            [columns] => Array
                (
                    [fid] => Array
                        (
                            [type] => int
                            [not null] => 
                            [views] => 1
                        )

                    [list] => Array
                        (
                            [type] => int
                            [size] => tiny
                            [not null] => 
                            [views] => 1
                        )

                    [data] => Array
                        (
                            [type] => text
                            [serialize] => 1
                            [views] => 1
                        )

                )

            [list_field] => 0
            [list_default] => 1
            [description_field] => 0
            [widget] => Array
                (
                    [file_extensions] => png gif jpg jpeg
                    [file_path] => articles-thumbnail-image
                    [progress_indicator] => bar
                    [max_filesize_per_file] => 
                    [max_filesize_per_node] => 
                    [max_resolution] => 0
                    [min_resolution] => 0
                    [alt] => 
                    [custom_alt] => 0
                    [title] => 
                    [custom_title] => 0
                    [title_type] => textfield
                    [default_image] => 
                    [use_default_image] => 0
                    [insert] => 0
                    [insert_styles] => Array
                        (
                            [auto] => 0
                            [link] => 0
                            [image] => 0
                            [imagecache_thumbnail_actualite] => 0
                            [imagecache_reg] => 0
                            [imagecache_gallery_assist-gallery_assist-thumbnail-100] => 0
                            [imagecache_gallery_assist-gallery_assist-preview-550] => 0
                            [imagecache_group_images] => 0
                            [imagecache_thumb] => 0
                            [imagecache_member_list_image] => 0
                            [imagecache_user_picture_meta] => 0
                            [imagecache_profile_pictures] => 0
                            [imagecache_thumbnail_two_col] => 0
                            [imagecache_thumbnail_author] => 0
                            [imagecache_short] => 0
                            [imagecache_thumbnail_one_col] => 0
                            [imagecache_tiny] => 0
                            [imagecache_gallery_assist-default-thumbnail-100] => 0
                            [imagecache_group_images_thumb] => 0
                            [imagecache_40x40] => 0
                            [imagecache_gallery_assist-default-preview-550] => 0
                            [imagecache_thumbnail_one_col_promoted] => 0
                            [imagecache_thumbnail_teaser] => 0
                        )

                    [insert_default] => auto
                    [insert_class] => 
                    [insert_width] => 
                    [label] => Thumbnail Image
                    [weight] => 0
                    [description] => 
                    [type] => imagefield_widget
                    [module] => imagefield
                )

        )

)