Yes, the problem was change the servername.

when select @@servername returns null, the jobs are not created.

I had the same issue and after i have corrected the servername the jobs were created.

@@Servername of null can happen if there is no entry in sys.servers for server_id 0. check sys.servers with this:

select * from sys.servers

steps to correct:

sp_dropserver '<servername>' -- if exist a one with the correct servername but id different from 0

sp_addserver '<servername', local

restart service:

source: http://social.msdn.microsoft.com/Forums/sqlserver/en-US/f5405442-2ab9-4e9f-8688-2e8ce5dae853/servername-returning-null?forum=sqldatabaseengine