diff --git a/make-includes/build_document_rules.make b/make-includes/build_document_rules.make
index 0e939bf..cdc2fbe 100755
--- a/make-includes/build_document_rules.make
+++ b/make-includes/build_document_rules.make
@@ -409,12 +409,12 @@
 #
 install-questions:
 	@$(TEST) -d $(HANDBOOK_INSTALL_ROOT)
-	@$(MKDIR) $(INSTALL_DIRECTORY)
+	@$(MKDIR_P) $(INSTALL_DIRECTORY)
 	@$(foreach f,$(QUESTION_INSTALL_FILES),if $(TEST) ! -f $(INSTALL_DIRECTORY)/$(f) -o $(f) -nt $(INSTALL_DIRECTORY)/$(f); then $(ECHO) "Installing $(f)"; $(CP) $(f) $(INSTALL_DIRECTORY); fi;)
 
 install-answers:
 	@$(TEST) -d $(HANDBOOK_INSTALL_ROOT)
-	@$(MKDIR) $(INSTALL_DIRECTORY)
+	@$(MKDIR_P) $(INSTALL_DIRECTORY)
 	@$(foreach f,$(ANSWER_INSTALL_FILES),if $(TEST) ! -f $(INSTALL_DIRECTORY)/$(f) -o $(f) -nt $(INSTALL_DIRECTORY)/$(f); then $(ECHO) "Installing $(f)"; $(CP) $(f) $(INSTALL_DIRECTORY); fi;)