Virtuemart 2 duplicate products pages

[NDanilov2015]

Good Evening!

I am administrator of the site http://alcopribor.ru. (Joomla 2.5.6, VirtueMart 2, PHP 5.3.10 on the hosting). This is e-commerce site for sell apparatuses that make home-made Russian vodka ("samogon"). The site has problem of duplicate pages - for example, the product "Samogonnyj apparat Katyusha" has two URL:
a) http://alcopribor.ru/apparaty-serii-dobrovary/apparaty-dobrovary/samogonnyj-apparat-dobrovar-katyusha-detail
b) http://alcopribor.ru/samogonnyj-apparat-dobrovar-katyusha-detail

My client ask for me that I remove second URLs and keep only first URL "with categories and sub-categories" in all products in VirtueMart.

How can I perform this task?

[jjk]

I don't know why this happens. On this page the the first url matches the canonical url, which is correct:
http://alcopribor.ru/apparaty-serii-dobrovary/komplekty-na-apparatakh-dobrovar/komplekt-distillyator-dobrovar-khozyain-skorovarka-9-litrov-detail
It's strange that the first url you posted above actually shows a duplicate slash on the website:
...://alcopribor.ru/apparaty-serii-dobrovary//samogonnyj-apparat-dobrovar-katyusha-detail

However, whatever the reason for the two different urls is, I think is dosesn't do any harm, because the search engines will probably index only the canonical url.

You could try to update to the latest versions of Virtuemart and Joomla to find out if that solves the problem.

[NDanilov2015]

Duplicate slash is result of internal redirect from duplicate categories in URL:
http://alcopribor.ru/apparaty-serii-dobrovary/apparaty-dobrovary/samogonnyj-apparat-dobrovar-katyusha-detail
Second "apparaty-dobrovary" is removed when we hit Enter in browser address input field => keep duplicate slash!

I can write [ANY_WORDS] instead of double category (or between "first" and "second" slash) , and we don't see duplicate slash:
http://alcopribor.ru/apparaty-serii-dobrovary/anywords/samogonnyj-apparat-dobrovar-katyusha-detail
Such URL opens without duplicate slash, but such URL is duplicate page too!

[NDanilov2015]

PS. I am NOT using sh404SEF , instead I am using the default Joomla SEF. May be SEF related with my problem?