Getting CDFs to work when embedded in my blog was giving me fits. I would get to the point where the my model  would work fine in a Mathematica mathbook, in a CDF preview, in the web-ready CDF run locally , but not when uploaded to my blog. Wolfram support advises that the option SaveDefinitions->True should be used in every CDF you create. SaveDefinitions->True preserves the internal state of all the variables for a CDF. I’ve used this now in CDF using Manipulate and DynamicModule and it definitely works.