problems in the financial system can impair the transmission of monetary policy to the real economy.
That is not only true in theory, you can see it clearly in the data.
Despite short rates near zero and $85B/month in Fed purchases total* bank loans and leases grew only ~$76B for ~6 months of 2013 (~1%, not even keeping pace with inflation).
The transmission mechanism is not functioning well and fiscal restraints are certainly part of the problem.