Make sure that CS2D is executed with the necessary rights and that write protection for the file or the corresponding folders is not enabled.
Never execute CS2D in C:\program files\... when using Win Vista, 7 or 8. It won't have any write permissions in this location.
Check if the stats folder in the settings is correct:
New Game
More Settings (Tab)
Scroll down to the stats section
Check the setting stats_folder (should be sys\stats or another valid location relative to the CS2D main folder)
Also check if the file is currently opened/in use by another program.
Remove the file (it doesn't contain any data. It is auto generated from the data which is stored elsewhere so you can safely do this without losing any stats.)
Re-start your system and try again.
In case everything fails or if you're just lazy: Try what Ahmad suggested.
Anywy, i didnt play alot in the New game server
so i didnt save alot of stats
i reinstaled cs2d and copied the file.html, pasted it in cs2d folder, remplace, now work, thank u