Sound problems with Paltalk Express

SOUND GETS CAUGHT AND LOOPS OVER AND OVER REPEATEDLY. MANY ARE HAVING SAME PROBLEM. WHEN SOMEONE GETS OFF THEIR MIC, A SNIPPET OF THEIR VOICE GETS CAUGHT SOMEWHERE AND LOOPS THROUGH MY COMPUTER. I AM IN PALTALK EXPRESS AND USE VISTA. IT WILL NOT GO AWAY UNLESS I LOG OUT AND COME BACK ON. I HAVE UPDATED FLASH AND JAVA. DON'T KNOW WHAT TO DO. OTHERS DON'T KNOW WHAT TO DO EITHER. PLEASE, CAN YOU HELP US? TECHIES HERE IN HELP COULD NOT FIGURE IT OUT EITHER.