Checkout workflow problems

It looks as though it should be really simple, but I'm having huge problems with the checkout workflow. I see how it's supposed to work (I think), and that 'end' has to be a separate step, but I can't find a way of setting 'end' as a step at all. Please see attached screenshot, showing the error message that I've been getting. I have tried to set 'Advanced checkout workflow edition' to 'no', so that maybe I can see more clearly what is going on, but I just get the same error message and it reverts to 'yes'.

I am using the 'Essentials' edition of HaikaShop with Joomla! 2.5.4, having just abandoned the horribly buggy VirtueMart 2 after years with VMart. Most of this looks a lot easier to use, so it's frustrating to come up against something I can't sort out for myself. Any advice gratefully accepted.

OK - I have partly solved this myself, in that I've found that I can turn off 'Advanced checkout workflow edition' in Internet Explorer (I was using Firefox), and I don't get the error message there. I have also been able to change other configuration settings in IE, when in Firefox anything I attempted just got me back to the same error message and changes were not saved.

However, the final checkout step fails to reach PayPal. Instead I get a white screen. Hey-ho...

Thank you, Nicolas, for that very quick reply. After I clear the cache in Firefox the error message disappears briefly, but comes back as soon as I try to save any changes. However, everything works fine in IE, and the PayPal process is now working. The public end of the site seems to work fine in Firefox, so I'll just have to go on using IE for the admin side.

However, I now have a problem with account creation. I'll check the forum, and post that separately if I can't find an answer. These problems are miniscule compared to the ones I was having with Vmart 2, and overall I love HikaShop! I'll be posting a glowing review on the Joomla! extensions site just as soon as I've finished setting it up.