Attempting to attach to Integration Services on a multi-instance machine with SSIS installed gives the error
Failed to retrieve data for this request. (Microsoft.SqlServer.Management.Sdk.Sfc)
Invalid Server name "Servername\instance". SSIS does not support multi-instance, use just servename instead of "servername\instance".
SSIS on SQL 2005 servers running multiple instances is not intuitive to configure. One 'instance' of SSIS controls all SQL Server instances and cannot be addressed by an instance name. This is particularly frustrating if you have a SQL server with no default instance as it results in a connections being flat out refused.
It can, however, be configured to recognize multiple MSDB databases on the same machine which effectively provides the same functionality.
To add a new instance, add a new Folder Record to the MsDtsSrvr.ini.xml
Backup the config file %SQL Install Root%\90\DTS\Bin\MsDtsSrvr.ini.xml
The default file should look something like (click for a more clear view)
To add an instance, add a new Folder Record
xsi:Type = "SqlServerFolder"
name = "MSDB Myinstancename
Servername = "server\instance"
You may need to restart the SSIS service to attach