Suspension error pages like those are also a standard message for accounts that go over their monthly bandwidth allotment.. something which could have happened if it's been sending out mIRC 6.33 to a lot of people .. So again, it's not a big deal. The mirror should be temporarily removed, but these things happen.. it's not all that serious or anything related to an exploit (don't know where that came from). Nobody's being blocked from downloading mIRC-- as I said, there are *multiple* mirrors (hence the concept "mirror"), so if one exceeded a limit, just try it again and use another mirror, it will work.
