odd error message

My emac running 10.4.11 will start running real slow at times. When this happens I get this error message, a script in this movie is causing Flash Player 10 to run slowly. It the asks if I want to abort the movie which I click yes.
I never watch movies on my mac and have no idea why this is happening. Any ideas on why this is happening or *** to fix this would be greatly appreciated.

Must be a flash banner on a web page, Flash runs badly on an Intel Mac so its especially crappy on a G4

Try running firefox on that G4 and add a flash blocker to speed up your surfing

Thanks for the help, I will run Firefox to see if there is a difference.