Problem with switching among the product categories

[dimarini]

Hello,

I am developing a website using a template with J1.7 and VM2. The domain name is http://lotos-u.com/.
There is a serious problem with switching among the pages in a product category.
One of the categories "Комплекти Acousma" (should be reached from "КОМПЛЕКТИ") contains several pages of products. Other product categories contain only one page of products.
When the category  "Комплекти Acousma" is chosen and left showing the first page of products everything is all right. But when this category is left showing say the second page of products the problem appears! Namely, when switching to a different category it is trying to show the second page of products, and surely there is nothing to show.
When the category "Комплекти Acousma" is switched back to the first page of products everything is back in place.
Where to search and how to fix this problem problem?

Thank you and Best Regards!