As far as I recall, this is an indication of an electronic fault in your transmission's controls.
However, this is based on my memory, which could be faulty. In a case like this it is best to consult the experts. Luckily, those experts wrote the Owner's Manual, so I strongly suggest that you open the manual and read every section that pertains to either the transmission or the instrument panel warning lights.
If I am correct, it is important to have this looked into a.s.a.p. by an independent transmission shop (NOT AAMCO, Lee Myles, Cottman, or any other chain operation). Failure to repair an electronic fault promptly usually results in much more expensive mechanical repairs to the transmission.