A question regarding an error message

Discussion created by engr1 on Mar 9, 2012
Latest reply on Mar 26, 2012 by nan-esristaff
I am running the VRP problem from for the file offered on the on-oline training vourse offered through ESRI. I keep getting the following message:

Warning: Impedance attribute is not time-based.
Error: Invalid context.

I redid the problem several times and each time I got the same message. Could you please help me out? Thanks.