Since the DDOS yesterday, MtGox turned off API support for anything calling the older https://mtgox.com/api pages and is now only allowing orders to be placed through their data.mtgox.com url calls.

I haven't looked on the forum much but didnt see this announced anywhere. Over the next few days I imagine others who run bots will pick up on this, fix their code and re-start their bots.

*edit* To clarify, I believe the API functions to query order response / account data were changed.