Mine is not working fine either since I have upgraded to the latest version. Especially if someone registers using a yahoo.com account.
I am on a Linux host (I have had far less problems than I did with Windows).
Also, this may not matter, but try putting in a / (forward slash) so your root reads as:
I am awaiting a reply on another thread here, but if that fails I am going to try uninstalling and reinstalling the entire product. Sometimes that helps too.
Good luck Skerett!