Problem using spellchecking function

I have a problem using the spellchecking function in the Studio 2015, run on Parallel Desktop. All the spellchecking dictionaries are come in the Studio 2015. It simply doesn't work. Every time I want to open the Editor options, I get the info "There is an error in XML document (0,0, Root element is missing. After playing around, restarting the software, I finally manage to get into the Editor options. After choosing Spellchecking, I get yet another error message: "Failed to create setting page." I need to click on a different tab, e.g. Autocorrect or the like. Only then I can get back to the Spelling tab. However, the Spelling tab view is literally distorted. After I click "Save", I receive another error message: "Object reference not set to an instance of an object." I really don't know what do to, I tried this: http://kb.sdl.com/#tab:homeTab:crumb:7:artId:4457 and this: http://kb.sdl.com/kb/?ArticleId=4393&source=Article&c=12&cid=23#tab:homeTab:crumb:7:artId:4393 none of it worked. Anyone has a different idea?