Moving TDE database to a new database but having problems with the cert
You will need to create a master key on the new server - if it does not exit already. 

USE MASTER;
GO
if not exists (select 1 from sys.symmetric_keys where name = '##MS_DatabaseMasterKey##')
 CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'Strong_Password';


Then you have to restore your certificate:

CREATE CERTIFICATE serverCert  FROM FILE = 'C:\cert_Backups\servercert.cer'     
WITH PRIVATE KEY (FILE = 'C:\cert_Backups\servercert.key'
    ,DECRYPTION BY PASSWORD = 'strong_Passw0rD')
GO 


But for this to work you will have to make sure that you made a backup of the original certificate with the private key.

Backup certificate ServerCert 
 to file = 'C:\cert_Backups\servercert.cer'
 with private key (file = 'C:\cert_Backups\servercert.key',
 encryption By Password = 'strong_Passw0rD')
GO


If you only have a cer file and not a key you will need to backup your certificate again