Database Mirroring for Disaster Recovery

I am trying your failover.sql script and it is working well up until the last step where it has failed over and needs to set the mode back to asynchronous on the new principal server. I am seeing the following error and wonder if this last step is even possible since it is being initiated on the server that just became the mirror? The alter database for this partner config values may only be initiated on the current principal server for database 'dbname'. Do you have any ideas what might be happening here? Thanks.

While I found the info in this article informative and useful, it might have been better titled "Database Mirroriring for Maintenance Windows." All the activities described assume that both sides are available. Disaster recovery is ususally about cases where the principal has become unavailable. The article would have better fulfilled its title had it covered descriptions (including compare and contrast with log-shipping, particularly with regards to data loss) and instructions for making the secondary a primary when the primary is not available.