You don't know that firms working on Polish highways have been screwed by middlemen, hand picked by the government and paid by the government?
Oh dear. Ironside, where did you read such rubbish?
The story with Polish highways is much simpler. The GDDKiA have been operating with a heavy commercial focus - they have been insisting on contracts being completed exactly to specification, combined with delaying payment until the last possible day. It's quite unknown for a government agency to work like this in Europe, and many constructors were caught out by the attention to detail. What makes it even worse is that many contractors were caught doing things that they shouldn't have been doing - and the GDDKiA were holding them to account and being rather ruthless about the whole thing.
The end result was that many foreign companies that expected to make a quick buck in Poland found themselves in deep trouble - they had bid intentionally low knowing that they could cut many corners with construction, but then the GDDKiA's attitude (fix it or we keep the huge bonds required and sue you) meant that costs were higher than they expected.
I fail to see why you can have a problem with the GDDKiA ensuring that the Polish taxpayer got value for money. It's also worth pointing out where contractors haven't been messing around, construction has been remarkably fast in Poland compared to Germany or France.
Many contractors have been messing around elsewhere too - Alpine (responsible for the A1 mess at Mszana) for instance have been pulling the same tricks all over Europe because of their messy financial situation.
