Button stops when i use Serin

[SuB-ZeRo]

loop:
button porta.4 ,0,0,0,b1,1,show 'AND I CAN'T GET THE BUTTON PUSH
serin portb.1,4,B0 'IF I USE THIS COMMAND THE PROGRAM STOPS HERE
if b0=1 then goto ok
goto loop

It is a simple code.If other pic sent data "1" then other pic will show with led
but when i use serin command program stops and wait data "1" and when program stops i cant get the button commands if i remove serin command the program works well but i need serin command coz i want to use remote.

Any suggestion?