If you are using the assignment tool for students to submit work please be aware that the process won’t work if the student is using Firefox 3 as their web browser. Firefox 3 will produce an error message saying ‘Please enter a valid file’ when an attempt is made to upload a file.
At the current time, you should advise students to use Internet Explorer (or at least avoid Firefox 3) when submitting work through the assignment tool in Blackboard.
Please see the following posts for more information about the assignment tool:
Assignment tool vs digital drop box
Posted by Jo 
