Chaitanya, that rating on the 325 is very conservative and if everything is operating correctly(speakers should be set "small", although that isn't likely to be the problem)it's certainly capable(as you were told before)of driving the Axioms to an uncomfortably loud(and dangerous to hearing)level. As has already been mentioned, your description seems to suggest a short. If you haven't already done so, carefully re-connect all the wiring, even if it looks like there's no loose strand now.
A more remote possibility is an internal short in one of the speakers. Disconnect one at a time to see if a loud level without shutdown can be had without that speaker connected.
