Multiple URLs in CMS - duplicate content issue?

[ufmedia]

So about a month ago, we finally ported our site over to a content management system called Umbraco.  Overall, it's okay, and certainly better than what we had before (i.e. nothing - just static pages).  However, I did discover a problem with the URL management within the system.

We had a number of pages that existed as follows:

sparkenergy.com/state/name

However, they exist now within certain folders, like so:

sparkenergy.com/about-us/service-map/name

So we had an aliasing system set up whereby you could call the URL basically whatever you want, so that allowed us to retain the old URL structure.  However, we have found that the alias does not override, but just adds another option to finding a page.  Which means the same pages can open under at least two different URLs, such as http://www.sparkenergy.com/state/texas and http://www.sparkenergy.com/about-us/service-map/texas.  I've tried pointing to the aliased URL in other parts of the site with the rel canonical tag, without success.  How much of a problem is this with respect to duplicate content?  Should we bite the bullet, remove the aliased URLs and do 301s to the new folder structure?

[MLTGroup]

I've got a similar issue with my CMS solution where the .htaccess file creates the pages in the system but the 301 redirect page will actually show the query string. such as:

site.com/oldpage

should go to

site.com/new-page-format.php

however if i type in site.com/oldpage i'm actually seeing site.com/new-page-format.php?htaccess_query_string

I'm going to implement a rel=canonical string for the site and see what that does. So depending on how your cms solution is built the 301 redirect could cause additional problems.

As for the duplicate content issue I think it would be best to get that cleaned up.