Make sure nothing else is using the selected port, if your host machine is a Power Mac this problem could happen if you have the serial nub installed on this machine.
Make sure that all symbolic information compilation flags are turned on.
It will be displayed as assembly.
(TTE Index out of range) that type is not defined in the symbolic file.
Please recompile with MPW 3.2 or better.
Try closing some other applications and try again.
Please recompile your application and specify the option to generate a Sym file.