I'm sorry for your troubles while using TeamPulse.
Could you please give us more details about your issue. Is this happening only when you are trying to register a new user? Are you able to see TeamPulse admin page? Are you able to see portal page? Are you trying to create the new user throw the admin panel or throw the registration area? Do you recieve this error in any other case or just when you register a user?
Please check for browser errors in the browser console (open it with f12) and send us a screenshot.
Could you alse send us your Log files, they are usually located here (C:\Program Files (x86)\Telerik\TeamPulse\Logs).
I'm looking forward for your answer.