Please try these steps for authentication issues.

1) Disable the virus scanner in Fix-It
2)Disable any pop-up blockers or fire-wall programs on your system
3)In Fix-It, go to Help andthen About 
4) Select theChange Serial Number tab
5) Enter in your serial number and clickOk. 
6) Wait for the message that your serial number registered successfully.
7) Close and restart Fix-It 
8) Try running EasyUupdate.

If it still will not authenticate, please contact tech support for further assistance.