I am using a Mac and until recently have experienced no problems (Pretty much up 'till the new sounds were introduced). However... since then my browser will randomly quit, obviously resulting in a loss of game.

I have tried using the following browsers and all have had the problem...

Firefox
Safari
Opera

Any ideas, people are getting points that they shouldn't!

Virus scan.

You can have some malware or a virus

Can you try turning the sound off to isolate whether sound is the cause of the problems?

I don't test on Macs but I do try and resolve any reported problems. Are you using Java 1.5 or Java 1.6?
http://www.funkysnooker.com/help#playing_problems

Your browser may crash when the Java runtime has an unresolvable problem. When it closes it should leave a file hs_err_pid on your machine. If you can find this it should correspond to each time your browser and game has crashed.