If you wanna deploy Sharepoint 2010 with a SqlServer 2008 R2 ON ANOTHER SERVER, make sure that the domain account which will be used as Sharepoint Service has the dbcreator and securityadmin permission in the target SqlServer.
If securityadmin is not selected, you may have trouble to setup a search service application. All you need is delete the deployed search service application, add permission to SqlServer and re-create a new search service application.