Not bad.
Using flash 4, eh? Well... Whatever you have access to, I suppose.
Anyhow... This piece was pretty good. The charecters were well drawn and some time was taken to make lip movements look semi-synced. Theres a lot of room for improvement but altogether it's pretty good.
Suggestions: Basically, all I would say is continue to mess with different styles in flash. Play with shading techniques and try to avoid using the shape tools(making a wall or building with the box tool tends to look pretty hacky).
Spend more time on your backgrounds - maybe draw up a few more poses for each charecter so they look more animated.
But, like I say, really all this artist needs is time to develop a more expansive relationship with the techniques and capabilities of Flash.