Thanks Jay Sandhu, yes that solved the problem! Most of the errors related to "one-way" restrictions on the Route Layer which was easily corrected. However, I had a tough time trying to save results and had to repeat the procedure several times before I could manage to do it. The file size increased from 180MB to about 550MB. I have about 70,000 stops, and more than 30,000 routes. Is that normal?
I agree, ideally I should have mastered this extension before I made this an important part of my dissertation. Its an important, but small part.... hoping to learn along the way, and these ArcGIS forums are very useful! Thanks again for the help!
Regards, Sweta