Check this page: http://www.macecraft.com/news/116/
If you have a PT 2005 license, you can use PT 2006 at no additional charge -- just download to your new computer and install it. You don't have to uninstall the bad PT 2005 -- an install over should work, or install to a new folder.
I believe just about everything except the Registry Monitor (Snapshots folder) is backward compatible.
If you want to move such things as the PT 2005 Backups and Preferences, you'll have to try again to copy just those parts.
If you have a problem installing your license from the e-mail, http://www.macecraft.com/do_contact/ may help ...
Good luck!