User Import Problem

I’m setting of user accounts on an Xserve running 10.4.2 Server at a K12 school for 12 grades. An import file was created for each grade using Passenger. All of the grades imported ok but except for 3 grades. When I import it only imports 3 to 6 users. No error message is generated. I can manually create the accounts but don’t want to type 600+ usernames.

What log file can I look at for clues. Any other ideals?

Thanks,
Ed