Appears so. When clicking the 'Choose files to upload' button, one is greeted by this when using the latest, brand new version of Flash:
Error: Error #2176: Certain actions, such as those that display a pop-up window, may only be invoked upon user interaction, for example by a mouse click or button press. at flash.net::FileReferenceList/browse() at SWFUpload/SelectFiles() at Function/http://adobe.com/AS3/2006/builtin::apply() at flash.external::ExternalInterface$/_callIn() at <anonymous>()
Is this an actual bug affecting everyone? Head to the Adobe Flash site to upgrade your Flash if you haven't done so yet. If it is, perhaps someone could look into seeing whether or not it's in the development bug tracker, etc.