Error 25625 - not able to set up a user account

I am getting this error -- 25625 -- when trying to login to and continue setting up a user account.  All info is accepted (Name, Telephone No. and Password) and then it says that it can't do it, providing the option of "waiting" or "trying to clear cache."  It also says to contact support, but I don't see any option to contact support directly, so I'm posting here.  Some users were able to get their accounts set up just fine, but this one user is stuck.  I tried deleting and recreating the user account, but still no luck.  Any ideas?