Overall sales in Europe (their main market) are broadly in line with inflation and overall sales are up by 16%. So until Apple start selling in china (oh wait that will never happen as they are way to expensive!) Nokia have some captive markets
Their bad performance in North America affects their image in the English speaking web/press which I think is kind of contagious on this side of the pond too. I've been thinking about what they need to do to get some buzz going and I thought I'd never say this but they need carrier support from a major American operator.
I am not being alarmist. It isn't even just about apps. The N900 will not carry Nokia's image much longer, and image is critical. It doesn't matter if they can dominate the low to mid end, because the media will hate them as long as they don't have an "iPhone". It'll suddenly be uncool to have any kind of Nokia, and people will flock to Samsung.