Frame hiccup when converting to .flv?!

[asintu]

I just finished making a little flash animation and uploaded it on youtube. Since it was choppy when I uploaded the original flash .mov file I converted it to .flv but I get some strange behaviour. Look at the first bean on the top left, just before it's falling..it's like hanging there.

http://www.youtube.com/watch?v=aKPj40F_Y3s

It happens between the 0:01 - 0:03 time frame.

Any idea why this happens? Since in the original .mov file everything was fine.

Thanks.