Looks like the Kuler API is undergoing some changes. And, the team is no longer issuing new keys. Though, they plan to begin issuing keys in the future. We will be sure to post an update when new API keys are being issued. I'll also ask the team to post an update to the API page so this is more clear.
Sorry about that.
Dave, thanks for your quick reply, I figured something like this might be the case.
Is there any way I could just get a testing key, with the understanding the the API is unstable and subject to change? I really want to use Kuler for a small personal project of mine.
@benknight87: did you get the api key?