The solution is to leave "play audio effects and warning beep" turned off. This won't have any impact on your ability to create and edit web sites, it just means the program won't beep at you when there's a warning.
This behavior may indicate problems with the sound card or audio drivers on the computer in question.
Solution 1) Click on Tools 2) Click on Options 3) Click on the General tab 4) Uncheck "Play audio effects and warning beep"