I am new to this, help.,

This is a Error for my Heavy Rain Map. I spent quite a bit of money and waited 2 months for the makers to make it
I need your help so if you know someone who’s made maps or has done developing before. This would mean alot to me as i can’t fix this error and i’ve tried alot

NullReferenceException: Object reference not set to an instance of an object - SDG.Unturned.Provider.onDedicatedUGCInstalled ()
SDG.Unturned.DedicatedUGC.triggerInstalled ()
SDG.Unturned.DedicatedUGC.installNextItem ()
SDG.Unturned.DedicatedUGC.onItemDownloaded (DownloadItemResult_t callback)
Steamworks.Callback1[Steamworks.DownloadItemResult_t].OnRunCallback (IntPtr thisptr, IntPtr pvParam)
UnityEngine.Debug:LogException(Exception)
Steamworks.CallbackDispatcher:ExceptionHandler(Exception)
Steamworks.Callback1:OnRunCallback(IntPtr, IntPtr)
Steamworks.NativeMethods:SteamGameServer_RunCallbacks()
Steamworks.GameServer:RunCallbacks()
SDG.SteamworksProvider.SteamworksProvider:update()
SDG.Unturned.Provider:Update()
NullReferenceException: Object reference not set to an instance of an object - SDG.Unturned.LevelSavedata.fileExists (System.String path)
SDG.Unturned.GroupManager.load ()
SDG.Unturned.GroupManager.onLevelLoaded (Int32 level)
SDG.Unturned.Level.onSceneLoaded (Scene scene, LoadSceneMode mode)
UnityEngine.SceneManagement.SceneManager.Internal_SceneLoaded (Scene scene, LoadSceneMode mode)

yeeeeeeeeeeeeeeeeeeeeeet,yeeet