I'm guessing this is inlined JavaScript, in which case you need to break up your closing </script>
tag. I also made it more readable:
$("#frame").replaceWith(
"<script language='JavaScript' type='text/javascript'>"
+ "AC_VHost_Embed(2672266,206,206,'',1,1, 2279587, "
+ "0,1,0,'912832a3e8b02d79380c8352f2d497f6',9);"
+ "<" + "/script>"
);
The reason for this is so that the browser doesn't think that your </script>
inside the string is the end of the script block. Example:
<script>
// Doesn't work!
alert('</script>');
</script>
Your browser sees:
<script>
// Doesn't work!
alert('
</script>
');
</script>
In other words, your browser thinks the script ends the first time it sees </script>
. You can fix this by breaking the fake </script>
up into pieces.
<script>
// Works fine!
alert('<' + '/script>');
</script>