Opus does not attempt to change any browser home pages, so I think WinPatrol is showing a false positive there. You may need to contact WinPatrol support to ask them what is happening.
The only thing Opus may change that is in any way related to web browser configuration, at least that I can think of, is the setting for the default FTP URL handler. That would not affect HTTP or HTTPS URLs or browser start pages, however.
You may also want to verify the digital signatures on both the installer and the main program file (dopus.exe etc.) to make sure you have not downloaded an installer wrapped in adware/spyware or anything like that. If you got the installer from somewhere other than http://www.gpsoft.com.au/DScripts/download.asp then that is a possibility. (If that has happened, and the installer was modified, please let us know and we'll do our best to apply legal pressure on whoever is distributing a modified installer to make them stop).