Yes, you can prevent the screensaver from popping up. BlitzMax should probably have a way of doing this natively, but I don't think it does. You would need to write your own windows message handler, and look out for the WM_SYSCOMMAND message. When the WP data passed with a WM_SYSCOMMAND is SC_SCREENSAVER, that tells you that the system wants to run a screensaver. If your WNDProc Returns 0 when that happens, the screensaver is not allowed to start.
I'm not entirely sure what you need to do to get your own WndProc running with BlitzMax though. I do it, but I create my own window and don't use any Max2D stuff. That's the message though, so if someone can help you with setting up your own message handler, you'll know what to do with it.
EDIT: Oops, should have mentioned, this is Windows only. If you're developing on other platforms, the method used will be different.
I'm not entirely sure what you need to do to get your own WndProc running with BlitzMax though. I do it, but I create my own window and don't use any Max2D stuff. That's the message though, so if someone can help you with setting up your own message handler, you'll know what to do with it.
EDIT: Oops, should have mentioned, this is Windows only. If you're developing on other platforms, the method used will be different.