WordPress MU

Hello there,
I can't upload any file to my site from wordpress control panel. It always shows me an error message that says it can't create the folder..
I check the permission of the folder blogs.dir and it's 777... somebody told me to chomd the temp folder to 777... I tried but it did't work...
more info: at first my site was being work good with out problem until the server has a big problem and the moderator of it restore a previous backup of the site...
do you think any think about my problem...
I am waiting for your help...
thnks...

the problem still being in my site...
can any body help me...

Check for ownership of the folder.

do you mean the permission of the folder...
if you mean that.. the permission of blogs.dir is 777...
note: some wordpress sites on the same server has suffered from the same problem...
maybe the server owners stop some functions that disable the uploading at wordpress!!??

here PHP Configuration from my cpanel...
maybe it help finding the problem...
Language Options asp_tags Allow ASP-style <% %> tags. Off
File Uploads file_uploads Whether to allow HTTP file uploads. On
Paths and Directories include_path Windows: "\path1;\path2" c:\php\includes" .:/usr/lib/php:/usr/local/lib/php
Resource Limits max_execution_time 30
Resource Limits max_input_time 60
Resource Limits memory_limit 20M
Data Handling register_globals You should do your best to write your scripts so that they do not require register_globals to be on; Using form variables as globals can easily lead to possible security problems, if the code is not very well thought of. Off
Language Options safe_mode On
main session.save_path where N is an integer. Instead of storing all the session files in /path, what this will do is use subdirectories N-levels deep, and store the session data in those directories. This is useful if you or your OS have problems with lots of files in one directory, and is a more efficient layout for servers that handle lots of sessions. NOTE 1: PHP will not create this directory structure automatically. You can use the script in the ext/session dir for that purpose. NOTE 2: See the section on garbage collection below if you choose to use subdirectories for session storage N;/path
File Uploads upload_max_filesize Maximum allowed size for uploaded files. 20M
main zend_optimizer.version 3.3.3

new problem with one of the wordpress sites hosted on the same server...
when I tried to install a plugin automatic, it shows this message:

Warning: touch() [function.touch]: SAFE MODE Restriction in effect. The script whose uid is 748 is not allowed to access /tmp owned by uid 0 in /home/sqlbchu/public_html/wp-admin/includes/file.php on line 175

PHP Safe Mode is turned on in your PHP configuration. That is not a recommended setting for a production server and might be causing some issues.

new note:
when using easy upload plugin I have this problem:

Warning: ini_set() has been disabled for security reasons in /home/hmksoft/public_html/wp-content/plugins/wp-easy-uploader/wp-easy-uploader.php on line 793

do you think that stoping the ini_set() function is the reason of the main problem of uploading files by the main uploader of wordpress...
thanks for your help...

hello,
the problem of uploading files to the wordpress sites was fixed...
but the problem of the wordpress MU site still being...
I can't upload any file to my blogs...
the blogs.dir permission is still 777...
can you help me...
thanks...

hi,
these here the php info of my site...
maybe helps you solving my problem...
http://home.sqlb.net/phpinfo.zip
thnks...