I have the same issue!! But bradley plugin works fine, and with Heli plugin - I got this error, when try to spawn Heli in game:
NullReferenceException: Object reference not set to an instance of an object
NullReferenceException: Object reference not set to an instance of an object
at Oxide.Plugins.HeliSignals+HeliSignalComponent.SignalAborted () [0x00032] in <0db033f4cd884e48b3ba51687f144768>:0
at Oxide.Plugins.HeliSignals+HeliSignalComponent.CustomExplode () [0x00034] in <0db033f4cd884e48b3ba51687f144768>:0
Plugin compile and load without any error.