I’m sorry I just updated my file to fix the misleading message. Right now it’s trying to say that you need to be a subscribing member to use the feature. But I think that’s wrong thinking. I’m pushing an update later today to fix it.
No with your current license in place it should definitely load. I just checked my test install and it worked. The developer tools function depends on ACF5 working, which turns on with an active API key.