When trying to post with a 13.5 kB txt file attachment:
QuoteThe upload folder is full. Please try a smaller file and/or contact an administrator.
We have set the total upload quota to a rather small size (10 MB) knowing that even if we set it to 50 GB, people would fill it up in a few weeks either way. :)
I've deleted some old attachments, it should work for you now.