Todd, thanks very much for the quick reply.
Well... the faster part is good. :)
What might be causing this problem?
It sounds to me like a memory leak (reference counting error) in numarray.
Did you run the same code with older versions of numarray, or did you start with numarray-0.5?
How long does it take to fail?
This was my first stab at using numarray, so I haven't tried with prior versions. Not that this means anything, but it usually dies around 500 or so iterations through the optimization routine. For comparison, Numeric will cheerfully run for several thousands of iterations, multiple times, without complaint.
Can you mail me your code (or better, the smallest derivative of it which reproduces the problem)?
This might be a little complicated. I'll try stripping things down to isolate the problem.