diff --git a/controllers/front/SitemapController.php b/controllers/front/SitemapController.php
index aaa72b560..b064575cd 100644
--- a/controllers/front/SitemapController.php
+++ b/controllers/front/SitemapController.php
@@ -47,10 +47,22 @@ class SitemapControllerCore extends FrontController
 		$this->context->smarty->assign('categoriescmsTree', CMSCategory::getRecurseCategory($this->context->language->id, 1, 1, 1));
 		$this->context->smarty->assign('voucherAllowed', (int)CartRule::isFeatureActive());
 
-		$blockmanufacturer = Module::getInstanceByName('blockmanufacturer');
-		$blocksupplier = Module::getInstanceByName('blocksupplier');
-		$this->context->smarty->assign('display_manufacturer_link', (bool)$blockmanufacturer->active);
-		$this->context->smarty->assign('display_supplier_link', (bool)$blocksupplier->active);
+		if(Module::isInstalled('blockmanufacturer'))
+		{
+			$blockmanufacturer = Module::getInstanceByName('blockmanufacturer');			
+			$this->context->smarty->assign('display_manufacturer_link', (bool)$blockmanufacturer->active);
+		}
+		else			
+			$this->context->smarty->assign('display_manufacturer_link', 0);
+		
+		if(Module::isInstalled('blocksupplier'))
+		{
+			$blocksupplier = Module::getInstanceByName('blocksupplier');			
+			$this->context->smarty->assign('display_supplier_link', (bool)$blocksupplier->active);
+		}
+		else			
+			$this->context->smarty->assign('display_supplier_link', 0);
+			
 		$this->context->smarty->assign('PS_DISPLAY_SUPPLIERS', Configuration::get('PS_DISPLAY_SUPPLIERS'));
 		$this->context->smarty->assign('display_store', Configuration::get('PS_STORES_DISPLAY_SITEMAP'));