Help with code

[mister_e]

try

        @   __config _HS_OSC & _WDT_ON & _MCLRE_ON & _LVP_OFF & _CP_OFF
        DEFINE OSC 20
        
loop:   high portb.1
        pause 500
        low portb.1
        pause 500
        goto loop
        end

Also, read the following thread, at least POST#1 and POST#5
http://www.picbasic.co.uk/forum/showthread.php?t=543

if you're using PM, you will need to use

        @   device  pic16F648A, hs_osc, wdt_on, mclr_on, lvp_off, protect_off

instead of __CONFIG