The problem isn't directly GM's fault, as the automaker relies on a Dutch-based third-party company called Kroymans Import Europe to distribute these brands across the Atlantic. Due to slow sales caused by the global economic downturn, Kroymans has found itself with an "acute liquidity shortage." In other words, it's out of money.
GM and Kroymans are currently working on a new distribution deal, but in the meantime, a court has appointed an independent administrator to take possession of the 3,500 unsold vehicles currently sitting on Kroyman's 165 European dealerships.
[Source: Automotive News - sub. req'd]