Endless file upload loop

Wuala, only on one machine, attempts to upload a file every 10 minutes or so. The file does not exist, and so cannot be uploaded. The file doesn't appear in the 'Show Uploads' window, nor does it appear anywhere else that I can find. As best I can remember, I tried copying this particular file onto my W: drive through Windows Explorer with a number of other files; for whatever reason, I rebooted my machine in the middle of this transfer--and this particular file was left behind. Now, Wuala gives me an error message "Could not upload file.name" every 10 minutes or so. Solutions?