If you see the Error in USAdd User the first time you try to login to RefWorks there are two things to try.
If you see "Error, the Group code passed in null was invalid" you need to clear your cookies and cache. If that doesn't clear up the problem, please email email@example.com.
If you're off-campus and trying to login to either RefWorks or Write-N-Cite, you may be asked a security question. The question is:
Do you want to view only the webpage content that was delivered securely?
You must answer No in order to display the entire login page.