Bluetooth/CommMG issue?

I'm trying to talk to a Bluetooth device paired to my desktop.  When I pair it, it assigns COM12 as the output port.  My Bluetooth radio is one of those tiny USB dongles.

If I open a terminal emulator (putty.exe in my case), it opens fine, the "pairing" status bit on my device lights up, and it reacts appropriately to my typing "a" at the keyboard.

If I run the following script, I get a windows crash message saying  "AutoIt V3 Script has stopped working" when the _CommSendByte is called.  The second message is not produced.



#include <CommMG.au3>
$result=""
$portvalue=inputBox("Port Number","Port Number?")
$port = _CommSetport($portvalue,$result,9600,8,0,1,0)
msgbox(0,"$port",$port)
$value=_CommSendByte("a",0)
msgbox(0,"$value",$value)
sleep(5000)
Exit

I've used CommMG for lots of other chores with no problem.

Any suggestions?