Browser Crashes because of a flash player plugin (Mac)

[mainiac]

Recently my sister's computer has been acting up. She is young and goes on various sites like disney, webkinz, etc.. But recently, whenever you try to go on a site that contains a macromedia flash player plugin the browser crashes. After seacrhing online I figured out that it is because the flash player is not completly compatible with Mac. it said that one possible solution would be to run the browser in Rosetta mode, however when I followed the directions to change the browser to Rosetta Mode it didn't work (I was unable to change it to Rosetta). Here were the directions: right click the browser-> select get info->go to general info and change the setting to Rosetta. Any help on how to change the settings, or possibly any other solutions as to what the problem may be thankyou. P.S. She has an IMacG5 OS X. I am a Windows user so please make any instructions as simple as possible. Thanks once again!