Hello Kraig.Guffey,
I understand you are trying to do multiple in the adCenter Desktop Tool.
Couple things that I would like to know so i can assist you:
1. What is the URL are you trying to add?
2. Have to tried to Import using a CSV file?
If you can, Please Contact Support so someone will be able to look at your account to see if they can replicate this issue.
Thank you,
MS adCenter Support