Trans. Failsafe Program & Brake lights stuck on!

[rikos]

Hi everyone. I have an issue with my 2001 X5 4.4 with 160.000 km and I was wandering if anyone can share any experience on that.
About 8 months ago my transmission went off without any message on the board. I made a rebuilt on it and it's fine ever since.
Three months ago I changed radiator and a few weeks ago I changed alternator and water pump. All broke one after the other.
All those plus a few window regulators are my problems so far.
A few days ago I drove in the first heavy rain in Athens Greece. The next day, when I went to start the car the message "TRANS. FAILSAFE PROGRAM" appeared and at the same time the brake lights are stuck on.
I removed the brake switch, but the lights are still stuck on, so I figured it's a wiring thing. While removing the panels above the brake pedal I realized that a lot of water was on the floor and it looked like it came behind the lower plastic panel.
To check the transmission, I drove around a few blocks and it works fine. I can manually change gears and in auto mode or S mode all gears work fine without unusual noises. I opened the black box with the transmission ECU in and it's dry.

Any suggestions?
Thank you