The sp sp_dba_DAC created without any issues and is giving desired results when fired from within the SSMS.

However i'm unable to fire it from using sqlcmd. Getting following error:

HResult 0xFFFFFFFF, Level 16, State 1

SQL Network Interfaces: An error occurred while obtaining the dedicated administrator connection (DAC) port. Make sure that SQL Browser is running, or check the error log for the port number [xFFFFFFFF].

Sqlcmd: Error: Microsoft SQL Native Client : An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections..

Sqlcmd: Error: Microsoft SQL Native Client : Login timeout expired.

I found that SQL Server Browser was disabled, i enabled it and started it and again fired it. Still same error.