Can't load files - says disk full but it's not

I'm getting an error message when I try to update my pages. I recently deleted a number of unused files on the site to make more room, and clearly there is plenty of available room for this file. What's going on?

Here is the log:

150 Opening BINARY mode data connection for x.jpg.
An established connection was aborted by the software in your host machine.
426-Maximum disk quota limited to 100000 Kbytes
Used disk quota 30458 Kbytes, available 69541 Kbytes
426 Data connection closed, cannot write file x.jpg - disk full?