The brake warning is likely trying to tell you your CHMSL (Center High Mounted Stop Light), aka the third brake light bulb, is out. Replace it and the error may go away.
Also, corrosion of the connections of the bulb sockets/holders can cause a false error message (all if the lights are illuminating).
E38 2000 740iL Orient Blue
E91 2012 328xiT Alpine White
Passed on to new families:
E30 1987 325i Royal Blue
E39 2003 540i/6 Sterling Gray
R56 2010 Mini Cooper S British Racing Green