According to the manual, the Cruise Control is deactivated when you turn ESP off. Why your ESP is off, however, is another question. You should take the car to the dealer asap to get it diagnosed.
92% of all people suck at math. I am a part of the 9% who don't.
2008 ML320 CDI 4MATIC (W164) - Silver/Black
2008 C230 4MATIC (W204) - White/Black
2002 E320 (W210) - Silver/Black - Sold due to rust