Error when importing VM data in Hikashop

-- HikaShop version -- : 2.3.5
-- Joomla version -- : 1.5.26
-- PHP version -- : 5.3.29
-- Browser(s) name and version -- : Firefox
-- Error-message(debug-mod must be tuned on) -- : nothing

I want to migrate a Joomla 1.5 website with VirtueMart to J3.3 with Hikashop.

First I have installed J3.3 and SPupgrade and imported the categories and articles from J1.5 to J3.3.
After that I would instal Hikashop and import VM data (from J1.5 site) But... that is not possible

I read about installing Hikashop on J1.5 site. So I made a copy of the site and installed it on subdir j15/domainname.ext. Then wanted to import VM data (in Hikashop), but get an error:

There is no table with the prefix 'jos_vm_' in your Joomla database.

The prefix is good (I checked). What to do now?

Hello Jerome,

Yes, the copy of the site has all VM tables.
I tested the site once more and disabled sh404SEF and changed the configuration.php file (set the live-URL with the right URL) and then tested the import proces of Hikashop. It worked! This time I did not enter anything in the box 'Prefix of Virtuemart tables in your database :'

I think disabling sh404SEF was the solution.

Problem solved