Hello again,
I would ask you to send me some data, but I know this is patient-related, so instead, could you send me three screenshots?
1. For the naming issue, send a screenshot of the Load Locations dialog box as it is when you're loading some stops. I think what's happening is a field from your input data is being mapped to a field on your stops. When the input record has a null value for that field, Network Analyst auto-generates a name that is Location 1, Location 2, ..., Location x. When the input record has a value, that value is added to the Name field of the Stops. I'm guessing the input field contains the 4- and 5-digit numbers you're seeing.
2. A screenshot of the Network analyst window showing the paired stops to verify the stops are loaded properly. To do this, set up a partial problem by loading 10 or 50 pairs of stops only--not all 700+. Expand the Stops category, but don't worry about showing all the stops; a sample is fine.
3. The third screenshot would be of the Layer Properties dialog box--Specifically, the Analysis tab of the route layer. I'm particularly interested in whether you are using hierarchy or not. Although you can just tell me that, it would be good to see what other settings are enabled and disabled.
From what you said about solve working for 10 pairs, failing for the 700+ pairs, then failing thereafter, it sounds like this is a memory issue. However, I would expect you to get a memory warning. What happens when you do this:
Shut down ArcMap (clear out the memory).
Open it back up, and solve 25 pairs.
If that works, solve for 50 pairs.
If that works, solve for 75 pairs.
...
If you run out of memory at 700+ pairs, you'll get failures after that unless the route layer is removed or ArcGIS closed.
If memory is the issue, it may be running out of memory if you're solving without hierarchy and one or more stops is on a portion of the network that is disconnected from the rest of the network. (Imagine, for instance, a stop in a gated community and restriction is turned on that blocks the entrance to that community.) In that scenario, the solver will end up searching every edge in the network. Given you're using the North America data, memory would almost certainly be a problem. If hierarchy is disabled, enable it and solve again. You're less likely to run out of memory when using hierarchy since it search far fewer roads than an 'exact' solve.
Thanks,
Robert