The Taxonomy feature has not been activated
If you’re trying to create a managed metadata site column type on SharePoint Server 2010 Beta and it’s returning the following error:
The Taxonomy feature (Feature ID "73EF14B1-13A9-416b-A9B5-ECECA2B0604C") has not been activated.
Check this post.
Basically, you need to run the following command in the Command Prompt:
STSADM -o activatefeature -id 73EF14B1-13A9-416b-A9B5-ECECA2B0604C -url http://<server> –force
Don’t forget to change <server> to the name of your SharePoint server.