It might have had an effect but I think it is a minor effect. IMO, Germany's unemployment problems have been caused by the EU. The borders between most EU countries are wide open. Germany has incredibly restrictive labor laws which make it near impossible fire unproductive workers, and employers are required to give their workers a disproportionately high number of expensive benefits. Businesses are getting tired of this, and the high taxes imposed on them, and are moving out of Germany to countries with cheaper labor like neighboring Poland and Czech.
They can cook the books all they want but I don't see how Germany's unemployment problems are going to go away until their society as a whole realizes that overregulation of businesses and mandatory, overly generous benefit packages for workers is counterproductive. The government has been trying recently to roll back some of these welfare benefits but their efforts are being met with pretty strong resistance from a population that has expected the government to provide everything for them for decades.
Of course, I'm no expert on these matters, but I think I've been in this country long enough to at least be able to see the effects of major problems like this.