Check section Upgrading to a SQL Server 2012 Multi-Subnet Failover Cluster at

http://msdn.microsoft.com/en-us/library/ms191295(v=sql.110).aspx

Personnaly I think using SSIS 2012 (SQL Server Data Tools 2012 + Project deployment + SSISDB) is the best solution.

You can modulate your environnement with variables.

Seems to be a cluster problem.

Check this : http://social.msdn.microsoft.com/Forums/wpapps/en-US/ae7008a9-0b42-4a5c-a8c3-3446281733fe/add-node-failure-on-sql-2012-failover-cluster

It seems that there is nothing to do with the database, the authentication web service is not found.

You have to check in IIS where your web service is hosted.

A lot...

Try to get the root cause of the server error in IIS :

http://stackoverflow.com/questions/2640526/detailed-500-error-message-asp-iis-7-5