If so, then you have the wrong type of CFL bulb installed.
To use a compact fluorescent bulb on a dimmer switch, you must buy a bulb that's specifically made to work with dimmers (check the package). GE makes a dimming compact fluorescent light bulb (called the Energy Smart Dimming Spirals®) that is specially designed for use with dimming switches. I don't recommend using regular compact fluorescent bulbs with dimming switches, since this can shorten bulb life. Using a regular compact fluorescent bulb with a dimmer will also nullify the bulb's warranty.
Also most photocells, motion sensors and electric timers are not designed to work with a CFL. check with the manufacturer for the use of a CFL for these types of fixtures.
Dave - 360renos