It is funny, I was just working on my first Agent KiXtart script today. I was using the same code example from the kix samples scripts. I took a guess and added the following lines to give my agent time to speak (in addition to the $char.wait($req):

code:

      $myreq=$char.wait($req)
      Sleep 20
	 $=$char.hide()
	 $agent.connected = "0"

Better yet (for me) I stuck the script into a function so that I could place any text in to the comments.

code:
 
Function GetAgent($ReqMsg)
;;;(cut)...agent code
      $req=$char.speak($ReqMsg)
EndFunction

Hope this helps!
Cheers