People have problems with paths in Python (and arcpy) when they're starting out. There's the r'...' method, the double backslash method, and the forward slash method. Occasionally you'll see problems pop up either as the root of the problem, or a piece of the problem in a question.
Edit: The question has evolved, but in a case where it hadn't I think this question is still valid.
Based on the title, people would be unlikely to find this answer through regular search mechanisms.
Obviously in this case the asker wasn't asking 'How do I create paths to data in Python', but that's what the answer reflects. Changing the title lend itself to an answer wouldn't prevent others from answering too because there's only one answer really.
If it's clearly the only problem with the script in a given question then it can be the defacto answer you link to from now on when you see a common problem.