A few ideas, since there's really nothing technically 'wrong' with your file;
1... After it gives you that error message about not being able to display, go check the logfile /var/log/xorg.0.log and see if there's any hints in there.
2... Try a colordepth of 16 instead of 24. Really, you won't notice any difference, and if it works, you'll be happy
3... Verify that the horizsync range you have specified it correct for the screen. if it is too narrow, the screen won't be able to sync. The vertrefresh for MOST laptop screens hovers right around 60 hz so you should be fine there. just check the horizontal numbers.