- First check if both /wp-content and /wp-content/upload have 777 permissions
- Try entering the following snippet into your /wp-admin/.htaccess
<IfModule mod_security.c> <Files async-upload.php> SecFilterEngine Off SecFilterScanPOST Off </Files> </IfModule>
- If this doesn’t work, you are either a) using shared hosting with a non-typical or overly paranoid configuration or b) your Flash plugin doesn’t work properly.
Try updating Flash to version 9.x (or the latest), if it still doesn’t work you will have to use a WordPress plugin to suppress Flash uploading, at least until you can figure out what’s going on.