I see this is your first post so please allow me to give a little guidance; many times more details are helpful and this is one of those times. If you can provide what version ArcGIS you are using along with the service packs applied that would help out.
Just a guess but it sounds like you have a computer network issue. Is the geodatabase you are trying to create the network dataset within on a shared drive? Can you create feature classes okay within this geodatabase?
When you create a network dataset, it automatically creates a point feature class containing system junctions indicating the locations where edges in the network connect. Did you, by any chance, delete the junctions feature class intentionally or by accident? Otherwise, as Joe suggested, it might be some kind of error reading or writing to the geodatabase. Have you tried doing the tutorial more than once, and did you get the same error each time?
Dear Joe Borgione, Thanks for the reply. I am using ArcGis 9.3 on PC workstation, windows 7, service back 1. answers to your questions: 1- No, the geodatabase which i am trying to create the network dataset is in my PC drive not shared drive. 2- Its ok, i can create a feature classes within this geodatabase.
I will check our network setting again. But can i ask, how can a computer network issue affects the results of ArcGIS?
Dear Melinda Morang, Thanks for the reply. No i didn't delete the system junction shapefile. Actually in the final step , after the new network shapefiles have been created, i try to build the network but it always failed and gives me this error. Also, i have tried these tutorials using my personal Laptop (ArcGIS 10.1 , Windows 7, service pack 1), and there is no such error.
Are you trying to use the same tutorial and tutorial data on both your 9.3 machine and your 10.1 machine? I wouldn't expect that to work. Various improvements to network datasets have been made throughout the years, so the procedures and data used for the 10.1 tutorial might not work in 9.3.