Here are the errors that seem to be causing your issue:
MainFrameActions: Cooking (Windows): UE4Editor-Cmd: [2015.12.17-12.41.45:302][ 0]LogInit:Display: LogProperty:Error: UStructProperty::Serialize Loading: Property ‘StructProperty /Game/Structures/ItemMaster.ItemMaster_C:ItemData’. Unknown structure.
MainFrameActions: Cooking (Windows): UE4Editor-Cmd: [2015.12.17-12.41.45:302][ 0]LogInit:Display: LogLinker:Warning: Can’t find file ‘/Game/FirstPersonBP/FirstPersonOverview’
MainFrameActions: Cooking (Windows): UE4Editor-Cmd: [2015.12.17-12.41.45:302][ 0]LogInit:Display: LogUObjectGlobals:Warning: Failed to load ‘/Game/FirstPersonBP/FirstPersonOverview’: Can’t find file ‘/Game/FirstPersonBP/FirstPersonOverview’
MainFrameActions: Cooking (Windows): UE4Editor-Cmd: [2015.12.17-12.41.45:303][ 0]LogInit:Display: LogUObjectGlobals:Warning: Failed to find object ‘Class /Game/FirstPersonBP/FirstPersonOverview.FirstPersonOverview_C’
Go ahead and take a look at the struct mentioned in the first error message and see if you can fix that up. It’s possible that it was renamed or removed and it is still looking for it. After you fix that, provide the full output logs if there is another error. Thank you