000259 : Output event table properties are not valid
Ensure that you have specified the correct output event properties. That is, you must specify a valid Route Identifier field, event type, and measure field or fields. You must also specify the correct number of measure fields for your event type. Point events have one measure field, whereas line events require two. See Defining tables for more information on defining valid field names. For more information on defining event tables, see Linear referencing datasets in ArcGIS.