VM needs a master link, which should not be a category or anything. The first link you make to VM (be it a category or a product) in Joomla menu will be what VM uses for all Itemid.
1. You should have created a link to VM, and called it "Store" or "Shop" or something. Then create links to categories, etc, all you want to.
Solution: Find your link with itemid 52 (which should currently be a VM link with parameters), and label that Store, and make the link just a regular VM link (no parameters). Then make another link that idtemid 52 used to be.
With your SEF on, I cannot really troublehsoot more.