This new challenge could delay the ESM, but I don’t think it will. Constitutional courts in democratic countries are rubber stamps for the legislature and executive. The judicial branch is part of the government and acts to increase the government’s and its own power at the expense of citizens.
The German Constitutional Court will approve the ESM in plenty of time. If it doesn’t, the ECB will step in to monetize PIIGs debts with the tacit approval of the German politicians while the supposedly hawkish Bundesbank looks the other way.
The money printing will continue as long as the Swiss are able to hold up the value of the euro through SNB purchases in the open market.