Loaded MechJeb into KSP GameData folder and part becomes available. However after placing a part on my rocket the interface does not display and there is not button/button I can use to open the mechjeb functions.
i have the same problem, i have the mechjeb 2.1 and the ksp 0.22 and it´s not working properly. i can see th component and placed in the rocket but there is no button or windows where i could manage the mechjeb