invalid token error

I was testing features of our EShop installation today. I was not logged into EShop as a customer. Under one of our category pages I selected "Add to Wish List" and was presented with a login screen. I attempted to login and got a "invalid token" error on a white screen. After using the browser's back button I tried using the 'forgot password' link on the login screen and got the same message.

I then went to a product screen, added an item to the cart and selected checkout in the popup. I logged into EShop as a customer on the next page. I then selected "Add to Wish List" in a category page and was presented with a wish list screen with the correct entry.

The site is at www.sierrastorage.com/services/onlinestore.html .

Suggestions?

Hello Tim,
I went to your site and checked that. In the pop out window after clicking on the Add to Wish List, if you click on "login" or "create an account" link, you will be redirected to login page of Joomla www.sierrastorage.com/component/users/?view=login . It works properly. I didn't see "invalid token" error there.
Can you please remove all cache and test again?
Sincerely, Giang