Negative numbers occur when YouTube audits the view counts. There is not a problem at SocialBlade, it just means YouTube looked at your views and decided they made a mistake, or decided to change what counts as a view and the negative number is how this is displayed when they roll the counter back. If you ever noticed when videos get to about 300 views YouTube locks the view count. This is the beginning of their audit system. The same thing happens on a grander scale for your total video views which is why you sometimes don't see an update in your view count for the day, or again why it sometimes gets rolled back showing you a negative number. Update: As of December 2012 it appears YouTube decided that if you delete a video you lose the views that were on there so many channels lost a large number of views.
EDIT: For those interested:
Bieber is about to get stripped of views too so