diff --git a/frappe/installer.py b/frappe/installer.py
index 3ce2bdf293..634d6287f8 100644
--- a/frappe/installer.py
+++ b/frappe/installer.py
@@ -242,8 +242,8 @@ def install_app(name, verbose=False, set_as_patched=True):
 	# install pre-requisites
 	if app_hooks.required_apps:
 		for app in app_hooks.required_apps:
-			name = parse_app_name(app)
-			install_app(name, verbose=verbose)
+			required_app = parse_app_name(app)
+			install_app(required_app, verbose=verbose)
 
 	frappe.flags.in_install = name
 	frappe.clear_cache()
@@ -579,7 +579,7 @@ def add_module_defs(app):
 		d = frappe.new_doc("Module Def")
 		d.app_name = app
 		d.module_name = module
-		d.save(ignore_permissions=True)
+		d.insert(ignore_permissions=True, ignore_if_duplicate=True)
 
 
 def remove_missing_apps():