Problem with Compiling

[skimask]

I tried to do a really simple blink led, but my code won't compile!
Every time I try to compile:

@ DEVICE PIC16F877A, HS_OSC, WDT_OFF, PROTECT_OFF, LVP_OFF
DEFINE OSC 20
LED VAR PORTB.2

TRISB=%00000000
PORTB=%00000000

main:
low LED
pause 1000
high LED
pause 1000
goto main
END

I get an error message that says I have an undefined symbol 'pic16f877a'
What can I do to fix this?

Which version of PBP are you using? 2.??
For that matter, did you try simply really hard to read the green manual?