Receiving 403 (access forbidden) when CFID or CFTOKEN are in the URL

We are running Coldfusion in production and I am setting up a developer edition for local development.  When I enter http://someServer.com/ml.cfm?aID=378 it works just fine.  When authenticate and start passing session CFID & CFToken (http://someServer.com/ml.cfm?aID=378&CFID=12345&CFTOKEN=54321), I receive the 403 error page.  Is there something in Coldfusion that is throwing the error?