Err: BARO-2 Err: BARO-0 in log file

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Hi, I am new to the quadcopter scene, I have just finnished building a 650 with APM2.5 with prodrive 28-36 1800KV with 9x5 Carbon Props and 30Amp HobbyKing ESC with Ultra Sonic Sensor, Go-Pro Pan-Tilt gymbal.

My first flight it took off high then landed. Downloaded log files and found that vibrations were very high.
Replaced bent prop adapter and installed a vibration damper platform for the APM.
2nd Flight much better very stable, very happy. Got an audio prompt stating altitude warning 400 feet. Thought this was strange, landed and went home and downloaded logs and found that there were a few BARO-2 and BARO-0 errors not sure why.
APM is in a case the hobbyking case.