missing buttons

Hi everybody, here is my frustration:
I created some wave effect in my file and in flashplayer it works ok, but when I put my swf file into any browser it seems towork slower and it misses some of the buttons in the row.
How can browser miss rollover and rollout action of the buttons in the row?
P.S.I have no heavy animations, just tweening the size of the letters.
Thanks, Pashunya

I have checked swf on pc and it works ok, so a problem is probably within macs and swfs and browsers?