I have the current version of LInuxMint 9 installed and configured with no screensaver (and all related options I can find turned off). The display is still going blank after five minutes (or so).

The computer has neither a keyboard nor a mouse plugged in. I am controlling it through a remote desktop (VNC) connection. The image on the remote screen does not blank out, but the physical display does.

What can I do to disable this. I need the screen to stay on no matter what for 12+ hours at a time.

Look at Preferences->Power Management, set "Put display to sleep when inactive for Never"

That was already done. I have also gone into Startup Applications and turned off the Power Manager daemon.

Are you sure you disabled screensaver in Preferences->Screensaver?

Yes. I also changed the screensaver to be something other than a blank screen, so I could tell if it was activated. That's not what's happening.

In addition to the physical screen going blank after a few minutes, it's staying blank when I do things on the screen using a remote desktop (VNC) connection. As I've said, the virtual desktop does not go blank. It stays visible. It is only the physical one that changes (and stays off until a reboot).

Whatever screensaver this is appears to only care about physical mouse / keyboard activity. As I've said, mouse and keyboard activity through virtual devices (remote desktop via VNC) does not turn it off (the screen stays blank). I confirmed that movement of a physical mouse (not normally present, but connected before boot to test this) will bring the display back to life.

Apparently, updates to the display are not enough to avoid the blanking. I opened a terminal window and ran 'top' (which updates the screen every couple of seconds). It still went blank (absent mouse or keyboard activity).

All of what I've mentioned in this post was done directly on the fit-PC, without a remote desktop connection. And to reiterate, this is not the gnome screensaver, which is turned off and set to display the fiberlamp when activated.

maybe try to play with some options in the xorg.conf:

"ALL/1/General/DisplayDetect" "1"
"ALL/1/Port/2/General/EdidAvail" "2"
"ALL/1/Port/2/General/EdidNotAvail" "1"
"ALL/1/Port/2/General/Edid" "1"

I'm having exactly the same screensaver issue as BrotherRichard.
No keyboard and no mouse and all screensaving options (that I know) are turned off. But screensaver still activates a blank screen.

Is there any resolution to this?