User Login not working "Please login first" Messag

-- url of the page with the problem -- : hiralite.com/index.php/log-in
-- HikaShop version -- : 2.2.2/business
-- Joomla version -- : 3.2
-- PHP version -- :
-- Browser(s) name and version -- : Safari 6.1.1
-- Error-message(debug-mod must be tuned on) -- : Please login first

Hi, I looked through all the documentation and forum, but could not find any solution.
Whenever I go to the login page and I type in the correct username and password I am redirected to the same login page with the message "please login first"
Before it was working fine. The only thing I did meanwhile was working on the tax rates and zones, which should have nothing to do with that.
Sometimes I am getting the error message "please login first" and am redirected to the login page and sometimes I am redirected to the user profile page, instead of just doing the login.
I would really appreciate your help on that one.
thanks a lot.

I just found what the problem is, but I don't know how to fix it. When I want to create a new menu item and select Login form, instead of login form it creates the User profile menu item. I don't know how that happened or how to fix it.
Any help would be appreciated.

Thank you for your response, Nicolas. I could not solve the issue, but I could work around it, since the login module works, it is only the menu item login that has the issue. So I used the module instead of the menu item.