These mostly seem to happen in conjunction with Kerbal Construction Time when using the "warp to" button to finish up a build or launchpad reconditioning. Not sure if KCT is calling KAC with garbage or if the error is within KCT.
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
3/9/2015 4:29:08 PM,KerbalAlarmClock,Reducing Warp-Transition
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
3/9/2015 4:29:08 PM,KerbalAlarmClock,Triggering Alarm - KCT: Tethys I (Karbonite) Complete
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
3/9/2015 4:29:08 PM,KerbalAlarmClock,KCT: Tethys I (Karbonite) Complete-Halt Warp
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
3/9/2015 4:29:08 PM,KerbalAlarmClock,Actioning Alarm
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
Unpacking Thlassa I (High Orbit) Y1D199 Duna
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
3/9/2015 4:29:08 PM,KerbalAlarmClock,API-DeleteAlarm-Deleting:33f6410d043f4ddb9f7f072aa6f0b30b
(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)
NullReferenceException: Object reference not set to an instance of an object
at KerbalAlarmClock.KerbalAlarmClock.FillAlarmWindow (Int32 windowID) [0x00000] in :0
at UnityEngine.GUILayout+LayoutedWindow.DoWindow (Int32 windowID) [0x00000] in :0
at UnityEngine.GUI.CallWindowDelegate (UnityEngine.WindowFunction func, Int32 id, UnityEngine.GUISkin _skin, Int32 forceRect, Single width, Single height, UnityEngine.GUIStyle style) [0x00000] in :0
(Filename: Line: -1)