I agree with RON MARCUS.

The PIC16F84A does not have a serial port, so you MUST use SERIN and/or SEROUT.


As stated by SKIMASK, you need to define which compiler you're using.


And on a personal note:
It appears you need homework done. I recommend reading the sample programs provided in the PBP folder.


PS: Forgive my english, it's a little rusty.