Are you using Internet Explorer 7 and getting a pop-up dialog box or error message when taking a quiz (even during multiple choice only):

Do you want to allow this webpage to access your Clipboard?
If you allow this, the webpage can access the Clipboard and read information that you've cut or copied recently.

The following steps have been reported as fixing this issue:

1. From the “Tools” menu, select Internet Options.
2. Click the Security tab.
3. In the “Security level for this zone” area, click Custom level... .
4. Scroll down to the “Scripting” section, under “Allow Programmatic clipboard access,” click Enable.

The problem has not been reported to appear for Firefox or Internet Explorer 6.