Use the following Voicethread code to copy and paste and then embed in the other html widget box. Just replace the 5 digit number - the 38354 that appears here twice - with your voicethread code - may be 5 or 6 numbers):

<object width="800" height="600"><param name="movie" value="http://voicethread.com/book.swf?b=38354" />
<param name="wmode" value="transparent" />
<embed src="http://voicethread.com/book.swf?b=38354" type="application/x-shockwave-flash" wmode="transparent" width="800" height="600" /></object>