The problem with Aveng at the moment is that both its major markets (SA and Australia) are commodities driven. So with the slump in commodity prices both will cut back on infrastructures spending. This is why the order books are not looking great.
Unfortunately until commodities start improving, Aveng's revenues will be under pressure. And even if they do improve it will take time for the economies to recover enough to start spending again. Even with a positive NAV, if the company keeps making losses this NAV will quickly decrease and be forced to sell of assets just to stay in business.
I think Aveng is a solid company and should survive this down turn, but I fear it will be a really long time before the price starts to recover.