An Event Data Field node has the same data field selected more than once. You can correct this error either by selecting a different Event Data Field for the duplicate item or by deleting the duplicate item.
To select a different Event Data Field, right-click the duplicate item, select Select Item, and select a different Event Data Field from the shortcut menu.
To delete the duplicate item, right-click the item and select Remove Element from the shortcut menu.
Refer to Caveats and Recommendations when Using Events in LabVIEW for more information about using events in LabVIEW.