Character Stats Kit - Over 40 nodes to power your Skill point, Exp, Reputation and stats!

i am getting these errors can anyone help with them?

Error Blueprint Runtime Error: Accessed None trying to read property CallFunc_GetInterface_AsStats_Interface3 from function: ‘ExecuteUbergraph_StatsComponent’ from node: Buffs Resetted in graph: EventGraph in object: StatsComponent with description: Accessed None trying to read property CallFunc_GetInterface_AsStats_Interface3
Error Blueprint Runtime Error: Accessed None trying to read property CallFunc_GetInterface_AsStats_Interface4 from function: ‘ExecuteUbergraph_StatsComponent’ from node: Nerfs Resetted in graph: EventGraph in object: StatsComponent with description: Accessed None trying to read property CallFunc_GetInterface_AsStats_Interface4
Error Blueprint Runtime Error: Accessed None trying to read property StatSaveComponent from function: ‘SaveGame’ from node: Save ID in graph: SaveGame in object: StatsComponent with description: Accessed None trying to read property StatSaveComponent

i am using version 4.15

Thanks in advance