I was trying to upload this cover art:
http://www.albumartexchange.com/gallery/images/public/jw/jwilli-joytot.jpg

to this release:
http://musicbrainz.org/release/3a10c30a-2eab-4850-9d1a-44751fca7e35/add-cover-art

However, halfway through the upload I accidentally renamed one of the parent directories in which I had the uploading image. After I while I got an error in the place of the upload file selector thingy which looks like an iframe with some XML in it (see screenshot and XML below). Since I renamed the directory, I can understand I get an error.

However, ever since then, when I try to upload the file again, I keep getting the same error. I can't seem to be able to upload the file at all. (I'm not sure if renaming the directory where the uploaded file is could cause the initial error or if my browser just caches files it uploads).

The XML error that I get is as follows:

<?xml version='1.0' encoding='UTF-8'?>
<Error><Code>InternalError</Code><Message>We encountered an internal error. Please try again.</Message><Resource>uploadItem.py: uploading id = mbid-3a10c30a-2eab-4850-9d1a-44751fca7e35 using contribSubmit!
local dir = /3/incoming/REMOTE_SUBMIT/s3-584b7089-24a8-4b3d-b917-3d4bff82560d-mbid-3a10c30a-2eab-4850-9d1a-44751fca7e35
submitter = caa@musicbrainz.org
priority = -5
scribe = None
stubMeta = False
deleteAfter = True
derive = False
update = False
comment = s3-put
s3_keep_old_version = False
item_size_kb = None
complete_multipart_upload_id = None
complete_multipart_upload_filename = None
Checking for identifier availability...
code = not_available
</Resource><RequestId>0cc93ab4-5d7c-4d45-acec-df85afd351b3</RequestId></Error>