There we're a couple of things a little off in your config, so I've modified it and am posting it for you to try.
-TwinView screen driver was "Monitor", changed to "GeForce2 MX"
-MetaModes had a ";", changed to a ","
-TwinView option specified "1", removed, may work but not necessary
-SecondMonitorHorizSync set to "30-50" per NVIDIA README Appendix J
-SecondMonitorVertRefresh set to "60" per NVIDIA README Appendix J
Remember to back up your XF86Config-4 before replacing it with the one attatched to this message