Actually your posted example code compiles without error with the command line...

pbp -p16f84a test

Code:
	temp var byte ' initialize variables
	freq var byte
	m_servo var byte
	l_servo var byte
	r_servo var byte

	portb.7 = 0 ' set initial logic states to 0
	portb.6 = 0
	portb.5 = 0

	freq = 13 ' delay value

start:

	m_servo = 140 ' set servo position values
	l_servo = 140
	r_servo = 140

	gosub servo

	goto start


servo: ' servo positioning subroutine 
	for temp = 1 to 10
		pulsout portb.7,m_servo
		pulsout portb.6,l_servo
		pulsout portb.5,r_servo
		pause freq ' set frequency between 50 - 60 Hz
		next temp
		return
Ahh... pain... just realised your using PBC not the pro version... you are going to have to go through your manual and assign your variable names and Pins to allowed variables and pins.