Ok, try this...
Code:
@ device HS_OSC,MCLR_OFF,LVP_OFF,WDT_OFF,PROTECT_OFF
DEFINE OSC 4
temp var byte
main:
        for temp = 0 to 255
        pulsout portb.0, temp
	pause 18
        next temp
        for temp = 255 to 0 step -1
        pulsout portb.0, temp
        pause 18
        next temp
        goto main
END
This should do nothing more than swing the servo back and forth, from endpoint to endpoint. It'll probably hang up for a bit at the endpoints and might even move too fast or jerk around a bit trying to catch up to the program.
If it doesn't, you've got something else going on.
It all boils down to breaking it down to it's simplest form and building it back up again.
Try it and report back...