Debian :: Screensaver Goes On When It Is Disabled

I have this strange problem with screensaver (in fact i dont know if it is the problem, but it seems to be), i describe the problem next:I have a computer with debian squeeze installed. I use this computer only as a dumb terminal for showing information about companies, this means that it have no mouse nor keyboard connected to it. I configure autologin for a not-provileged user and autorun one app.

I disabled the screen saver for obvious reasons. This all works very fine. The problem is that when connect to the computer with ssh and reboot it, 10 minutes after started the monitor goes dark, as if the screensaver gets activated, then i connect a mouse and do some moves the screen goes to the normal functional state, then disconnect the mouse and it never goes dark again, after 1 day even!. When i turn on the computer with mouse and keyboard connected, just 20 seconds after started i disconnect those both, it do the same (after 10 minutes goes dark), but if wait for 1 minute usgin the mouse and keyboard and then disconnect both, the screen goes dark thing never came out. It just appear to happen at some point when the system does not detect any input.