Hi,
Sorry for the inconvenience, the source of your issue may be:
* ArcGIS Online having temporary trouble creating Feature Service. Did you give it a second chance another day?
* The FS creation really failed. You may see it in ArcGIS Online but it may be invalid
* The FS creation succeeded but Map Tour didn't received the response in time, so it consider it as failed
What you can do is to add your FS to the Map Tour webmap yourself through ArcGIS.com map viewer (use Add->Search for layers, it is important that you use that way and not Add->Add Layer from Web).
Then try to use Map Tour builder and see how it goes.