ERROR 130121: Input polyline features have existing calibration points

[Regulus]

Hi,

I am working through ArcGIS Roads and Highways: Introduction to Modeling and Data Management. Section 3: Exercise - Load LRS network data. I am trying to append source routes data to the CityNetwork feature class. The Geoprocessing tool, Generate Calibration Points, is giving me this error message. 

ERROR 130121: Input polyline features have existing calibration points

These are the details in the text file it creates:

"Number of route and existing calibration point combinations which had duplicate route IDs and time span overlaps: 913
Object IDs of routes and existing calibration points which had duplicate route IDs and time span overlaps:
(Format is 'ObjectID_in_input_polyline' + 'ObjectID_in_calibration_point')
488+930,318+566,1115+1802,1117" <many more of these numbers and +'s>

How can I get past this?  Thank you

[Regulus · Accepted solution]

I just re-did that section and everything went perfectly this time. I am not sure what went differently. But I noticed in Step 3L of Section 4, where it says "Click any route on the map to identify it," the pop-up showed the information. But Step 3M says, "Notice that in the pop-up, the measure information is not available." Then the next step is where I got the error message I referenced in the original post. Still if anyone has insight, I would be interested.