We are not using the homework module in our installation, so i am not sure, what the problem actually is.
In order to try to help you, i
- installed a fresh instance of DotLrn (from the oacs-5-9 branch),
- defined semester+department+class,
- uploaded as a student a "homework" file
- the professor could read the file
- the professor added a comment file
- the student could read the comment file
do this steps work for you as well?
did the professor create an additional folder?
As i understand it, the homework module is a specially tailored file-storage, where visibilities are managed via permissions. So, when the student uploads a file, all admins of this instance are granted permissions on this file (and vice versa for feedback comments). Can it be that there in your instance you have not the right admins defined?
all the best
-g