I'm unclear about what you mean by saying, "the CDD is in default." A CDD fee is a pre-development financial arrangement that allows developers to build without the normal burden of costs for infrastructure. These fees are passed on to the owners as an annual assessment for an agreed period of time (20-30years).
My recommendation is to approach both the county tax department and the builder(s) to try to get a handle on what this all means. It may not be time to run but it is very likely a time to get to the bottom of things. I just can't see how a CDD could be in default........I' like to hear more on this.