Help! with GUI

C:\Pylo\MCreator181\forge\build\sources\main\java\mod\mcreator\mcreator_forestryInterface.java:43: error: cannot find symbol
            if (ent != null && ent instanceof mcreator_workspaceCorgan.TileEntityCustom)
                                                                      ^
  symbol:   class TileEntityCustom
  location: class mcreator_workspaceCorgan
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: C:\Pylo\MCreator181\forge\build\sources\main\java\mod\mcreator\mcreator_forestryInterface.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

I create on the GUI tutorial the menu exactly as there, but in the tutorial it does not give an error, but it gives what to do?