Exception

Question

Hello!
 I made a MVC 3 Application. I have used EF (Database first). I have the skill and Candidate Controller.Inside of Candidate  controller I have a standard list format of create new, edit ,details and delete. Clicking on the edit occurs following exception for this line of code:
  private IEnumerable<CandidateSkillFormated> GetSkills(int candidateId)
  {
  var _ce = new CandidatesEntities();
  return _ce.CandidateSkills.Where(s => s.CandidateID == candidateId)
  .Select(s => new CandidateSkillFormated { SkillName = s.Skill.SkillName, SkillLevel = s.SkillLevel,
  CandidateId = candidateId, SkillId = s.SkillID}).ToList();
  }
Exception:
EntitityCommandExecutionException was unhandled by user code
An error occurred while executing the command definition. See the inner exception for details.