title: Changing .NET framework causes System.AccessViolationException
body: <p>I have a big problem which makes me cry everytime when I try to resolve it.
  I have installed VisualStudio2012 Express and  made project in  .net 4.5 framework it is simple project which use QUARTZ library and has only 2 lines:</p>
  
  <pre><code>var cron = new Quartz.CronExpression("0 * 8-22 * * ?");
  DateTimeOffset? nextFire = cron.GetNextValidTimeAfter(DateTime.Now);
  </code></pre>
  
  <p>I successfully have compiled application and it works fine. But one day I had to change framework from .net4.5 to .net 4.0 and  when i did it VisualStudio throws errors in line </p>
  
  <pre><code>DateTimeOffset? nextFire = cron.GetNextValidTimeAfter(DateTime.Now);
  </code></pre>
  
  <p>Exception is: </p>
  
  <blockquote>
    <p>"An unhandled exception of type 'System.AccessViolationException' occurred in WindowsFormsApplication6.exe
    Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt."</p>
  </blockquote>
  
  <p>I tried to change framework from net4.0 to .net4.5 because in .net4,5 application worked fine but it does not works! I can go back to .NET4.5 but application throws the same System.AccessViolationException.
  Have Anyone know how to resolve this issue?</p>