In some ways, I understand, but in most I do not. For some reason Adobe removed web services from ActionScript 3 in Flash. The web services classes we all used in AS 2 with abandon for no longer exist in the Flash API. Wow. This post offers up my research on getting around this issue.
I may be missing something, but a search around the Internet revealed several people having the same problem and not finding any good answers. You have an ASP.Net user control with fields on it, but when you compile you get an error. Intellisence knows the objects are there, but the compiler doesn’t. What do you do?