Apologies for the delay -- we're a small team, and sometimes responses take a little longer than we'd prefer. You can delete submissions themselves by clicking the "Reject and Archive Submission" link on the submissions' Summary page. Reviews themselves are not deletable -- they form part of the history of the submission, much like an uploaded document at a particular point in the review or editing process. If this is still a problem, you may want to look at how you enroll your Directors within the system -- if they submit to the conference and blind peer review is a part of their submission, they should definitely *not* be enrolled as either a Conference Manager or a full Director -- rather, enrolled as a Track Director if need be, and a managing director enrolled as full Director and so able to assign submissions.
Regarding the errors you are seeing -- can you tell me which version of OCS you are using?