Blog & User Creator added users said there was 1 error

Blog & User Creator added users said there was 1 error adding a user and no link or indication on what user the error was for or what the error was.
I only added 25 users but what if there was 1,000 users added. we will be sitting there checking a list for 2 hours.
So unless I missed something (it would not be the first time) Could we have a link or a list of what the error is and username of the error
thanks