I have installed opencart and I have also installed Arabic language and pavillion theme and I followed the documentation, but I get this problem:
PHP Fatal error: 'Could not include the language file /home3/smartgpt/public_html/project/catalog/language/english/default.php'
in /home3/smartgpt/public_html/project/tb_themes/pavilion/library/ResourceLoader.php:143
Stack trace:
#0 tb_themes/pavilion/library/ThemeManager.php(722): TB_ResourceLoader->loadOcTranslation('default')
#1 tb_themes/pavilion/catalog/ThemeCatalogExtension.php(302): TB_ThemeManager->loadOcTranslation()
#2 tb_themes/pavilion/catalog/ThemeCatalogExtension.php(94): Theme_Catalog_Extension->setLanguageDirection()
#3 tb_themes/pavilion/library/vendor/sfEventDispatcher.php(81): Theme_Catalog_Extension->afterRouting(Object(sfEvent))
#4 tb_themes/pavilion/library/CatalogDispatcher.php(130): sfEventDispatcher->notify(Object(sfEvent))
#5 tb_themes/pavilion/library/CatalogDispatcher.php(66): TB_CatalogDispatcher->doRouting(Object(sfEventDispatcher), Object(Request), Object(TB_ViewDataBag))
#6 tb_themes/pavilion/catalog/boot.php(48): TB_CatalogDispatcher->dispatch(Array)
#7 catalog/controller/common/tb_themes.php(32): TB_Boot::bootTheme(Object(Registry), Object(Front), 'pavilion', 0)
#8 [internal function]: ControllerCommonTbThemes->index(Array)
#9 system/modification/system/engine/action.php(65): call_user_func(Array, Array)
#10 system/modification/system/engine/front.php(42): Action->execute(Object(Registry))
#11 system/modification/system/engine/front.php(37): Front->execute(Object(Action))
#12 system/modification/system/engine/front.php(17): Front->dispatch(Object(Action), Object(Action))
#13 index.php(243): Front->addPreAction(Object(Action))
#14 {main}
Go to : /catalog/language/english/ ... Download english.php > rename to default.php > upload back to /catalog/language/english/
Because it is saying, that it could not include language file, because there is no such file in /catalog/language/english/ directory. Helped for me.