I can't seem to replicate this. A few questions:
- are you sure that the director notified the author using the email template under review that revisions are required?
- does the author see "Paper in review: revisions required" listed under the Status column for that submission, in their Active submissions queue?
- how exactly are they not allowed to upload the file? Eg. is the upload field on the submission's review page greyed out?
Regarding the multiple rounds of review question -- you are correct, OCS only has the one round currently. See http://pkp.sfu.ca/bugzilla/show_bug.cgi?id=2796
for more information.