You can stumble upon this issue when using Virtuemart 2.0.
VM2 introduced new language features and #__virtuemart_products_%lang% table now has language suffixes. These tables store product info data in different translations.
It may appear that the language used during VM installation doesn't match the current language chosen in Joomla or for any other reason there is a language mismatch.
The easiest way to find out the language used is to open phpmyadmin and check this table:



It is ru_ru in our example. So let's take it and specify this suffix in Options tab of Fast Seller:



That's it.