Problem with np.power in numpy 1.5.1-2

["M." <infinity.probability@gmail.com>]

Hi all,

I've been using numpy without problems - version .1.4.1-5 - until this
morning, when I upgraded my Debian sid system to numpy 1.5.1-2. A
function that was working that uses np.power

def get_far_field(self, chi, n):
       return np.sum(self.an[n,1:self.j] * np.power(chi,-np.arange(1,self.j)))

outputs "Warning: overflow encountered in power". I'm using python
2.6.6-12. Is this a bug in the numpy library or (more probably) my
code? If it's in my code, what can be happening? How to debug it?

Thanks