AVR-Chat

Dear,    
I need to use an attiny15 in my project and I am not having success. 
I tried this simple program,  the led doesn't turn offt. excuse for 
my English.  thanks a lot

Nailson

$regfile = "at15def.dat"
$crystal = 1000
Config Pinb.3 = Input
Config Pinb.4 = Output
Led Alias Portb.4
Do
If Pinb.3 = 1 Then
   Reset Led
   Waitms 500
End If
Set Led
Waitms 500
Loop
End