Dear Mackerel,
OK, I found 3.0.1 on D-Link's Taiwanese site.  This helped not at all, alas, as the minimize button still doesn't work, the app. sat there like a lox, displaying a couple of frames a second out of thirty and freezing, and was unresponsive for about two minutes before clicking the mouse on anything on the screen had any effect.  Using IE 8 and the ActiveX control displays the full thirty frames a second, as does IP Surveillance 3.x, which works rather well, indeed.  I believe I'll just use this alternative program and give up on D-ViewCam, for it's obviously not going to get better anytime soon.
Does anyone have any idea why D-Link IP Surveillance doesn't show-up on the list of applications for the DCS-6620G?  Thanks for your help!
Jeff Broido