Templating classes

I am working on a class that will be a matrix based on a vector of
vectors. I am having trouble with the following code causing errors on
compilation:

template<class T> class MatrixBase
{
   public:
      MatrixBase()
      {
         width = 0;
         height = 0;
         matrix.clear();
      }
      MatrixBase(const unsigned w, const unsigned h, const T &d = T())
      {
         matrix.resize(w, std::vector<T>(h, d));
         width = w;
         height = h;
      }

      void AddRow(const T &d = T())
      {
         for (std::vector<T>::iterator i = matrix.begin(); i !=
matrix.end(); ++i)
            i->push_back(d);
         ++height;
      }
      // More methods
   protected:
      std::vector< std::vector<T> > matrix;
      unsigned height;
      unsigned width;
};

In the AddRow method (and other, similar methods as well), it says
that it needs an ';' before i and that it's undeclared. It also says
that 'height' and 'width' are undeclared. Should I move the variable
definitions up to the top of the class or should the methods be
outside of it entirely?