MovieClipLoader Events Don't Exist in Class Files?

This is interesting… I’m writing an AS2.0 component that extends the UIComponent and I have the following movieClipLoader defined in the init() function:

movieClipLoader_mcl = new MovieClipLoader();

movieClipLoader_mcl.onLoadProgress = loadProgressRoutine;
movieClipLoader_mcl.onLoadComplete = loadCompleteRoutine;
movieClipLoader_mcl.onLoadError = loadErrorRoutine;

SEPY and MTASC don’t seem to have a problem with the code, but Flash gives me the following error:

Line 54: There is no property with the name 'onLoadComplete'.
             movieClipLoader_mcl.onLoadComplete = loadCompleteRoutine;

The really strange part is that even though I get this error at compile time, the actual event handling functions (ex. loadProgressRoutine) actually run when they’re supposed to. So even though Flash is complaining about the properties in the MovieClipLoader not existing, it uses them when it has to…

My question is “why is Flash complaining” and “how do I make Flash stop complaining?”

Thanks very much in advance…