Welcome to the portal
If this really is your first movie, then WOW! You sure are off to a great start. The animation is really good, the graphics are good, and the sound is good as well. However, in terms of regular quality, it isn't too fantastic, but still, when first-time authors impress me, it's hard not to say really good things!
A few pointers for creating better flash: Make it longer, and place more detail. That waterfall sure was cool looking. However, this is 2009, and the bar of quality in flash movies overall is really high now. Another pointer is don't make trailers, but this is an OK exception. Plus, sometimes flash authors really need the publicity, I can understand. As well, try making custom sprites for certain situations. Funny faces and funny looking stances come in handy in comedy sprite movies.
I hardly see any flash authors with first movies that get past the portal's judgment. However, this might be a rare exception.
Maybe you're the chosen one...heh.