You currently have the pin that is to be receiving the character set as an output.

PortB = 0:TRISB = 0

Since the debug mode is 1, it's using inverted rs232. Inverted rs232 will idle low, so as long as it's idling everything will be ok.

Once you try to send something the input will go high, but since the pin is set to output and initialized low, you effectively have a short. This will cause a reset.

Also, there is no Define DEBUGIN_BAUD
The IN baudrate is always the same as the DEBUG_BAUD

HTH,
    Darrel