"The ETLadmin account, which is a domain account that we use it to run SSIS packages, does not have the right permission to access views in that database even if it has sysadmin permission on that SQL Server instance."

Could the author please explain this a bit further? How can a database user with sysadmin permissions on the instance not be able to read any data it wants? I admit that with only 4 years DBA experience I'm not a SQL Server guru, but I find it hard to believe that this is truely the case.