这是什么情况？

Exception in thread "main" brut.androlib.AndrolibException: brut.directory.PathNotExist: apktool.yml
at brut.androlib.Androlib.readMetaFile(Androlib.java:244)
at brut.androlib.Androlib.build(Androlib.java:268)
at brut.androlib.Androlib.build(Androlib.java:258)
at brut.apktool.Main.cmdBuild(Main.java:233)
at brut.apktool.Main.main(Main.java:88)
Caused by: brut.directory.PathNotExist: apktool.yml
at brut.directory.AbstractDirectory.getFileInput(AbstractDirectory.java:103)
at brut.androlib.Androlib.readMetaFile(Androlib.java:240)
... 4 more
I: Using Apktool 2.0.0-Beta7 on SystemUI_src