Hi mrlabu,
I am having a similar issue to yours. I uploaded my resume/cv a month ago, and at that time I had no problems opening up the files which I had uploaded. Until recently, however, I had problems opening up the files. I am not sure if it's a general technical issue that applies to all applicants though.
Perhaps it may be good to email/call them to enquire. Since they have already informed you to come down for an interview, it should be fine for you to make these queries.
anyway, wish you all the best!