What went wrong - well, when Thor sent in their audit team in anticipation of the purchase, they found accounting irregularities of sufficient nature to make them refuse to include the Roadtrek Canadian operation from the bigger international purchase. According to news reports several senior executives have already been summarily dismissed. No one wants to publicly admit exactly what the nature of the irregularities are, probably because of pending lawsuits.
It should also be noted that Hymer has only owned the Roadtrek Cdn company for 3 years. 3 years ago Roadtrak employed 300 people total. As of yesterday when the company went in to receivership, the layoffs totaled somewhere around 900 personnel. That sounds suspiciously like the company was expanded way, way too fast. It's not like it's Ford adding another plant, that's a highly unusual expansion rate, even in a booming industry.
Receivership is not the end of the world for the Cdn corporation. Chances are it will come out of bankruptcy and, while it will be on a shoestring budget and a smaller production, it just might survive the whole thing. No one will know until the accountants get done finding all the irregularities.