GUI problems

Hey guys,

First of all I want to ask if somebody can speak german and if not, its no problem.

So my problem is I use MCreator 1.6.3[1.7.10] and if I try to add a GUI it says:

Executing gradle command: build
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. Alle Rechte vorbehalten.
C:\Pylo\MCreator163>cd forge
C:\Pylo\MCreator163\forge>SET "JAVA_HOME=C:\Pylo\MCreator163\jdk\"
C:\Pylo\MCreator163\forge>SET JAVA_EXE=%JAVA_HOME%\bin\java.exe
C:\Pylo\MCreator163\forge>SET PATH=%JAVA_HOME%\bin\;%PATH%
C:\Pylo\MCreator163\forge>gradlew build
****************************
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****************************
:compileApiJava UP-TO-DATE
:processApiResources UP-TO-DATE
:apiClasses UP-TO-DATE
:sourceMainJava
C:\Pylo\MCreator163\forge\build\sources\java\mod\mcreator\mcreator_gUIachievements.java:139: error: cannot find symbol
if( ent != null && (ent instanceof mcreator_genBlock.TileEntityCustom))
:compileJava FAILED
                                                    ^
  symbol:   class TileEntityCustom
BUILD FAILED
  location: class mcreator_genBlock
Total time: 9.438 secs
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.
C:\Pylo\MCreator163\forge>
Task completed with return code 0 in 10071 milliseconds

And I don't know what I did wrong

Please help me, you can also add me on Skype: krabbeindahood

Yes I know weird name xD 

Thanks a lot

Steven Vetter