Well, I'd never say anything was impossible but its more likely that you'd have a double engine shutdown, or something just as bad.
There is a shaft that runs from the middle of the left wing, through the belly where the 2 flap motors are, and all the way out to the middle of the right wing. So that basically covers the basis that all 4 of the flap panels will come out together. In fact, the CRJ100/200 is known for having a flap system prone to failing due to this fact. It is a flexible shaft on those airplanes (that allows it to make the turns in the wing) that can get kinked. There are numerous sensors on the flap actuators that make sure they all turn at the same rate, and if it detects that just one is off just the slightest bit, it will shut down the flap system and you'll get the "FLAP FAIL" caution message.
So, I guess the answer to your question is yes and no. Yes, asymmetric flap deployment is possible, but there are so many protection factors that prevent the flaps from coming out wrong that it disables the system to prevent such a thing happening.
Make sense?