Below is a link indicating a delay in the launch of the AMC-16 satellite. A part on the Flight Termination System on the Atlas V needs replacing. The Flight Termination System is used to destroy the launch vehicle if a major malfunction occurs during ascent that causes the launch vehicle to go off course and is a safety feature employed on all launch vehicles. It doesn't state how long it will take but if only a part needs to be swapped out, the delay should be a week or less.
http://spaceflightnow.com/tracking/index.html
http://spaceflightnow.com/tracking/index.html