How can i trace this error to find what causes it ?

Code:
C:\Users\CASA\Documents\WebsIDIQ\Cesilabs_com_esigest\html\esinube_desarrollo\ap
licaciones\esitareas>sencha compile -classpath=.\,app,..\..\libs\extjs_v4_1_1_a\
src,..\..\libs\extjs_cesi page -yui -in manel.php -out build/index.php
Sencha Cmd v3.0.0.230
[INFO ]         Compiling page null
[INFO ]         Processing classPath entry : C:\Users\CASA\Documents\WebsIDIQ\Ce
silabs_com_esigest\html\esinube_desarrollo\aplicaciones\esitareas\sencha-compile
-temp-dir
[INFO ]         Processing classPath entry : .\
[INFO ]         Processing classPath entry : app
[INFO ]         Processing classPath entry : ..\..\libs\extjs_v4_1_1_a\src
[INFO ]         Processing classPath entry : ..\..\libs\extjs_cesi
[INFO ]         Processing classPath entry : C:\Users\CASA\Documents\WebsIDIQ\Ce
silabs_com_esigest\html\esinube_desarrollo\aplicaciones\esitareas\app
[ERROR]         Circular extends reference :
Ext.layout.component.Dock ->
Ext.layout.component.Dock
[ERROR]         Error executing page compilation Circular extends reference for
class Ext.layout.component.Dock
[ERROR]         com.sencha.exceptions.ExCircularReference: Circular extends refe
rence for class Ext.layout.component.Dock

C:\Users\CASA\Documents\WebsIDIQ\Cesilabs_com_esigest\html\esinube_desarrollo\ap
licaciones\esitareas>pause
Presione una tecla para continuar . . .