I finally have time to work on my code, and YES! I got it work!!

There are few things I changed:
1. For the single digit display, I changed my output from PORTA, to PORTB.0~3. Since then, it displayed numbers from 0-9!!!

2. For the servo, I changed the PULSOUT signal from potential to potential*2, because, the full motion range 0-255 is for 4MHz, but I'm using 8MHz indeed.

Thank God!!!