Spain, and other Euro countries, have "paper" laws. Everything needs to be printed out and stored to make raids like these easier on the government. It also keeps their tax authority from ever having to worry about modernizing and, frankly, makes it easier for the government to manufacture "irregularities."
I think the financial crisis in some of these EU countries have reached a point where they are politically paralyzed (can't move to the right due to strong leftism in the electorate) so they'll just find a way to milk multi-nationals to keep the lights on. This isn't a long term strategy and is a sign of some bad stuff coming up. I believe in the long run the welfare state is unaffordable and without a move to the right these countries will suffer, especially as business moves to more tax friendly jurisdictions and leaves these markets over government abuse, low sales, low margins, etc.
Currently, Spain has 25% unemployment and almost 50% for those under 25. The GDP is falling at the same rate it is for France and Italy. The sudden interest in these countries to raid multi-nationals for tax reasons is no coincidence here. France just raided Google's office last month. I suspect Italy is next.