i am wp-beginner and have the same problem - with the wordrpess 3.5.1 i can not upload the images properly. - there is the message that a upload failer occured (but no further information)
when i use the browser-upload, i come to a new emty site (http://mydomain.ch/wp-admin/media-new.php) - but nothing happens.
when i use the multiple uploader there is also a failure.(it uploads the images, but the process stopps suddenly)
when i check afterwords my mediabox- the pictures are uploaded, but it's impossible to edit them. (message: 'there is no image-data, please upload image again)
i also tried to deactivate all my plugins - still the same!
i also checked and changed my functions.php file after visiting - but without success.