Ignore the dll things, thats just stack information for debugging, the real errors are mentioned before those, here i filtered importent stuff:
Ensure condition failed: ReferencingPin->LinkedTo.Num() > PinData.ArrayIdx [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 1393]
Ensure condition failed: GIsTransacting || Pin->LinkedTo.Contains(ReferencingPin) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 1410]
Ensure condition failed: GIsTransacting || Pin->LinkedTo.Contains(ReferencingPin) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 1410]
Ensure condition failed: GIsTransacting || Pin->LinkedTo.Contains(ReferencingPin) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 1410]
Ensure condition failed: GIsTransacting || Pin->LinkedTo.Contains(ReferencingPin) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 1410]
[Compiler PersistentLevel.02_Serwerownia] Error Could not find a function named "OFFSCREEN" in 'KomputerMonitor2_Blueprint_C'.
Ensure condition failed: ToPin->LinkedTo.Contains(this) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 333]
UATHelper: Packaging (Windows (64-bit)): Cook: LogOutputDevice:Error: UEdGraphPin::BreakLinkTo Pin 'frac' on node 'Inputs' not reciprocally linked with pin 'B' on node 'float / float'
LogOutputDevice:Error: Ensure condition failed: ToPin->LinkedTo.Contains(this) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 333]
UATHelper: Packaging (Windows (64-bit)): Cook: LogOutputDevice:Error: UEdGraphPin::BreakLinkTo Pin 'frac' on node 'Inputs' not reciprocally linked with pin 'B' on node 'int * float'
UATHelper: Packaging (Windows (64-bit)): Cook: LogInit:Display: LogOutputDevice:Error: Ensure condition failed: GIsTransacting || Pin->LinkedTo.Contains(ReferencingPin) [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\EdGraph\EdGraphPin.cpp] [Line: 1410]
UATHelper: Packaging (Windows (64-bit)): Cook: LogInit:Display: LogOutputDevice:Error: UE4Editor-Engine.dll!0x00000000DE65516E
UATHelper: Packaging (Windows (64-bit)): Cook: LogInit:Display: LogBlueprint:Error: [Compiler PersistentLevel.02_Serwerownia] Error Could not find a function named "OFFSCREEN" in 'KomputerMonitor2_Blueprint_C'.
UATHelper: Packaging (Windows (64-bit)): Cook: LogInit:Display: LogOutputDevice:Error: Ensure condition failed: ToPin->LinkedTo.Contains(this) [File:D:\Build\++UE4+Release-4.16+Compile\Sync
By look of it you blueprints are broken or corrupted. You said you been moving project around, you sure you did it correctly and copy everything? because it looks like you have some reference issues in blueprint, asset don’t connect to themselves. biggest hint is this: Could not find a function named "OFFSCREEN" in 'KomputerMonitor2_Blueprint_C'. check if everything is fine in there also there some metion of math nodes, try relink them if you figure which one are broken. Best way to fix blueprint data issues like those is to delete broken stuff, create them again and relink them so blueprint data is recreated properly in the graph data and asset data.