Summary: After installing Directory Opus, Internet Explorer displays an error message when starting indicating that it is no longer the default browser.
This problem is triggered by turning on the option which makes Directory Opus the default FTP handler.
When Internet Explorer starts it automatically checks to see if it is still the default web browser and FTP handler; if it isn't either it will complaing by display a warning dialog, unless you have told it to stop checking during startup.
Unfortunately, even if you tell Internet Explorer to make itself the default browser again, it is not smart enough to modify the FTP settings and this dialog continues to appear every time you start the browser.
There appear to be only two ways to prevent the dialog:[ul][li]Tell Explorer not to perform the check on startup any more, by turning off the Always perform this check when starting Internet Explorer option in the warning dialog. (This is the recommended solution).[/li][/ul]Or:[ul][li]Disable the option in the Directory Opus Preferences which makes Opus the default FTP handler:
Settings->Preferences->Miscellaneous->Make Directory Opus the default handler for FTP sites.[/li][/ul]