Flash Access supports SWF and AIR app whitelisting, which means that a license can specify that content may only be played in certain SWF or AIR applications. A SWF can be identified by its URL -- in this case, if you change the URL for the SWF, but only the original URL is specified in the license, then playback should fail, and the client should return error 3310. Alternatively, a SWF can be identified by a hash of the SWF content. If you make changes and recompile the SWF, teh hash value would change.
Check the policy used to package your content to see if a SWF whitelist has been specified, and if necessary, update the whitelist with your new SWF's URL or hash. If nothing is specified in the policy, check your license server to see if it is overriding the information in the policy.