Autoloader won't upload files as it reports that "Another user is currently using Autoloader. Please wait"
How To
This indicates that at some time in the past there has been an "autoload" attempt from another machine or perhaps even this machine which has failed. When an "autoload" operation is initiated a hidden file is placed at the top of the Vault working folders, Vault Explorer ($), and locks access.
If you go to your Vault Explorer options and select "Show hidden files" the file BUU.xml will appear.
You need to "Undo Check Out" on this file to free the operation.