Odd Object Reference Error

In my code behind I have this:

List<StudentTargetsItem> studentTargets = new List<StudentTargetsItem>();         studentTargets = StudentTargets.Select(CurrentStudent.StudentID, CurrentSession.SubjectID);List<StudentTargetsItem> studentTargets = new List<StudentTargetsItem>();
studentTargets = StudentTargets.Select(CurrentStudent.StudentID, CurrentSession.SubjectID);
(Sorry, code insert popup not working so just text)
For some reason I get the error on the second line: Object reference not set to an instance of an object. 
But its set on the line before???

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