Julie,
You should be able to click the Validate All button, and it will convert the question mark(s) to a green checkmark for all that are successfully registered.
As far as the warning when publishing the service, just ignore it. It will let you publish the service with warnings, just not with errors and should work fine in searchwidget.
What is the format of table you are using? FGDB, SDE, oracle table/view, etc? If you add it to ArcMap as an event theme, do you get a warning about the table not having an Object-ID field?
R_