The server SharingMatrix updated the upload service, and stopped working in the File & Image Uploader. Please update. Thank you.
12 February, 2010
Some news regarding our upload features:
1) We replaced our flash-based web uploader to a more reliable ajax-based upload box. This should fix issues some people experienced while uploading files.
2) FTP upload as improved and allows now to upload files in folders and sub-folders, and appropriate folders and subfolders will be automatically created in your account.
3) Remote upload got "Upload from popular file sharing services" sub-menu, which makes remote upload from another file sharing services much easier.