Do you have any other cameras connected to your Mac by any chance?

Although I believe that the setting you make in QuickTime Player 7 only affects this particular application: what camera have you selected there (my setting there is "Automatic")?

Remote Buddy doesn't use any scripts. It uses a webserver of its own (IOSPIRIT RapidHTTPD). The error message you see is actually an image and sent by the server when it couldn't get exclusive access to the default camera device.

At this point, I don't have any idea why Remote Buddy would be the only application on your Mac that doesn't get access to the default camera device. Do you see any error messages under "All messages" in Console.app? If you want me to have a look, please open System-Profiler.app, select "Save", save a file in SPX format and send it to info@iospirit.com.

Thanks in advance.

Best regards, 
Felix Schwarz