error on adding menu

Hi,

I had successfully installed Hikashop, thanks for the great extension. However, when i link up the menu item with the products listing page am getting the below error

"Strict Standards: Only variables should be assigned by reference in C:\xampp\htdocs\site\plugins\system\hikashopuser\hikashopuser.php on line 16" and the page is not displayed.

and in the menu manager i am getting the below error


Strict Standards: Declaration of MenusModelItem::generateNewTitle() should be compatible with that of JModelAdmin::generateNewTitle() in C:\xampp\htdocs\site\administrator\components\com_menus\models\item.php on line 26

Strict Standards: Declaration of MenusModelItem::cleanCache() should be compatible with that of JModel::cleanCache() in C:\xampp\htdocs\site\administrator\components\com_menus\models\item.php on line 26

and on forcefully creating a menu item

Fatal error: Call to a member function clean() on a non-object in C:\xampp\htdocs\site\libraries\joomla\cache\cache.php on line 283