All dongle protection systems since pretty much ever have had issues with the computer's time.  I once spent a huge amount of time trying to work out why a FlexLM license to MotionBuilder wouldn't work.  Turns out a directory on the root of one of my hard drives was time stamped 10 years in the future (I think I was testing something).  But as a result the FlexLM driver (which uses a dongle but of a different design than iLok) decided my permanent license was no good.  Changing the timestamp on the directory fixed it.  Now it shouldn't have mattered, my license didn't have a time element but the software cared about the time it thought it was being correct and so failed.