In Windows Vista (not in Win XP), the "Download all" zipped folder contains all submitted and feedback attachments in relevant folders, but when the folder is unzipped, both attachment folders are listed as files of unknown type, and are empty.

To replicate:
As student: submit an assignment with both inline text and an attachment
As instructor:
- view the submisson, enter inline and summary comments, add a feedback attachment, grade, save
- click the grade link for the relevant assignment, click download all, save the zip file to a local drive, view the file before extracting
Result - the submission and feedback attachment folders are visible and populated with attachments
Extract all the files
Result - a message comes up "There is already a file with the same name as the folder you specified..." (see attached file
Click Skip button several times.
The extract process completes, and it seems that all the files have been extracted, but examination of the unzipped folder reveals that the submission and feedback folders are listed as empty files of unknown format