Looks like your system doesn't support displaying 640x480 resolution in fullscreen, which is the default setting for hi-res patch in RP. Many monitors don't support resolutions lower than 1024x768 nowadays.
I'd recommend you to check "Windowed" option, so Fallout 2 will start in windowed mode, and you can resize the window to any size you want.
Or if you want to play in fullscreen, don't check the option but choose one of the four available resolutions.