First off, let me say I'm not an installation person but I'll share with you what I understand to be true. I did not think the 'client' piece was a service so what service are you starting for that and getting an error? My understanding is the DMC is the client piece. My understanding is this: with the exception of the server referred to as LOOPBACK, if you have the service set to manual, you have to start it before trying to access it via the DMC. And if you close the DMC, it will not stop the service. For LOOPBACK, that is your local server and I believe that if you start the DMC and it's not running, it will start it for you. And if the DMC started it, when you get out of the DMC, it may close it for you. I always started and stopped the server on my own so I am uncertain as to the behavior if you let the DMC do it, plus, the release you are on may behave differently than what I've experienced.
If you are running this locally, go to (names not exactly right here but hopefully close enough) START, PROGRAMS, IWAY SOFTWARE, DATA MIGRATOR, and you should see a start and stop icon just for this purpose. If you have the service set to automatic, it will start everytime your local machine is started and and I believe it will not stop unless you stop it.
As for the error you are getting when trying to start the server, try using the start icon and see what happens. If you still get an error, and I'm assuming you are running locally, try changing the service for the server to automatic and restart your machine. If you still get errors, I recommend you open a case with IBI and request installation assistance.
I'm sorry I'm not more help. Good luck.
Data Migrator 5.3, 7.1, 7.6
WebFOCUS 7.1, 7.6, 7.7
SQL Server, Oracle, DB2
Windows