,
I would suggest making sure that the following are not referenced, renamed or moved within your new project:
[2015.12.04-17.34.26:431][ 0]LogLinker:Warning: Can't find file '/Game/Meshes/4plants/fernLeaf1'
[2015.12.04-17.34.26:431][ 0]LoadErrors: Info Failed to load /Game/Blueprinty/Istota/Postac.Postac_C Referenced by PlantLeafs
[2015.12.04-17.34.26:431][ 0]LogUObjectGlobals:Warning: Failed to load '/Game/Meshes/4plants/fernLeaf1': Can't find file '/Game/Meshes/4plants/fernLeaf1'
[2015.12.04-17.34.26:431][ 0]LogLinker: Can't find file '/Game/Meshes/4plants/fernLeaf1'
[2015.12.04-17.26.40:919][ 0]LogLinker:Warning: Can't find file '/Game/Meshes/4plants/fernLeaf1'
[2015.12.04-17.26.40:920][ 0]LoadErrors: Info Failed to load /Game/Blueprinty/Istota/Gracz.Gracz_C Referenced by PlantLeafs
[2015.12.04-17.26.40:920][ 0]LogUObjectGlobals:Warning: Failed to load '/Game/Meshes/4plants/fernLeaf1': Can't find file '/Game/Meshes/4plants/fernLeaf1'
[2015.12.04-17.26.40:920][ 0]LogLinker: Can't find file '/Game/Meshes/4plants/fernLeaf1'
If this does not help resolve your issue, could you please upload new from your project. Could you also try to import your project to a new, blank project and let me know if you run into the same issue?
Looking forward to hearing back from you, thanks!