Copying link to clipboard or pasting link to editor window gives me an error

When I try to copy a link to the clipboard or last a link into the editor window I get this error:
This feature requires 'signed.applets.codebase_principal_support=true' at about:config
How can I fix this. Also I have a mac and have been using safai and right clicking on documents to get the menu to copy, paste, and add meta data and so forth, doesn't work... I don't know why, the menu just doesn't come up. I get the standard browser menu. It works on firefox though, but still.

Thanks,

Becky