Yes, most likely you have an infection blocking malwarebytes from updating. I'm at work on my blackberry right now and can't post specific instructions and won't be home for another 5 hours or so. You would need to run either rkill.scr or combofix and then most likely you would be able to update. I will post links for the download sites when I get home unless Respital or Gamblingman comes online before then.