no matter what i do, the engine will crash.
click play:![alt text][1]
click compile:
here is the log:
[2015.06.07-02.32.43:326][996]LogWindows: === Critical error: ===
Fatal error!
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x00000030
UE4Editor-CoreUObject.dll!UObjectProperty::GetObjectPropertyValue() {0x000007feed15fa10} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UObjectProperty::SerializeItem() {0x000007feed2b6a94} + 21 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UStruct::SerializeBin() {0x000007feed19a143} + 275 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UStructProperty::StaticSerializeItem() {0x000007feed2ba61e} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UStructProperty::SerializeItem() {0x000007feed2b6bca} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UArrayProperty::SerializeItem() {0x000007feed2b51e7} + 39 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UStruct::SerializeBin() {0x000007feed19a143} + 275 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!UBlueprintGeneratedClass::AddReferencedObjectsInUbergraphFrame() {0x000007fee9b12f7b} + 24 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!FArchiveRealtimeGC::ProcessObjectArray() {0x000007feed22516c} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!TGraphTask::ExecuteTask() {0x000007feed1f8bd4} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FTaskThread::ProcessTasks() {0x000007feec79605e} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FTaskThread::ProcessTasksUntilQuit() {0x000007feec79628d} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FTaskThread::Run() {0x000007feec7a528b} + 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FRunnableThreadWin::Run() {0x000007feeca561c8} + 0 bytes [d:\buil