Strange SerOut Problem

[masosi]

I've tried the circuit with the Crystal (4MHz), everything seems to be the same...

Attached is the circuit diagram, could someone please check it to see what I am doing wrong please???

The LED blinks if the serial port is not connected to the computer.
The LED doesn't blink if the serial port IS connected to the computer, so I'm thinking its a grounding problem. Any suggestions?

This is the code that I am testing with:

PORTA = 0
PORTB = 0
CMCON = 7 'Set 16F628A Comparators off

Include "modedefs.bas"
light var PORTB.0
Low light

Start:
Toggle light
SerOut PORTA.1,N300,["Pulse",10,13]
Pause 100
goto Start

High light
end