I have used the transistor version of the Arduino Serial Board...
How can i debug my problem ?
Well you have to determine if you have a good serial link back and forth to the PC.
1. Remove the processor chip for this test.
2. wire a jumper from pin 0 to pin 1. This will cause a loop-back connection.
3. Launch the Arduino IDE, select the proper comm port number.
4. click on the Arduino serial monitor, anything you type and send in the transmit window should be echoed back into the receive window.
5. If you don't see data coming back, time for a scope to see which direction the serial data is failing.