The "dialog box is open" error message is used in Microsoft applications and its implications depends on the program it appears in. It may appear in Outlook webmail or in Microsoft Word 2003 or 2007. In Outlook, it may appear if the user has not completed the user information data for their version of Microsoft Office. In Microsoft Word, it can be an indication that the Officeav.dll file - which is the Norton-Antivirus Word plugin - is outdated or corrupted.
In Outlook, the problem can generally be remedied by simply entering the information into the user profile.
In Microsoft Word, the file can be found on the hard drive via a search and renamed with a different extension (for example "old"). The computer should then be restarted and the problem should be resolved.