The script is actually called "mysql_fix_privilege_tables.sql", ...if that helps. And it's located in the "scripts" folder of the mysql installation. I've installed MySQL 5.x on a WinXP machine. Accepting the default installation parameters, the scripted files were placed in a directory called c:\mysql\scripts.
If you're having trouble on a MS-Windows installation, you might want to check the PATH variable and consider any previous installations of MySQL that you might have on the machine. That could be interfering. I had mySQL 4.0.x installed(which installs to c:\mysql-4.0.x) and had some trouble on my system because when I tried to run the "fix" script, Windows kept looking through the 4.0.x installation directories.
You're on the right track. I see, in my installation, the two scripts that you do(of course, they're actually named "mysql_fix_privilege..."). But I've also got the "mysql_fix_privilege_tables.sql" file, that you seem to be missing.
Either your copy of MySQL was flawed and didn't come with the script, or the script was accidentally deleted/renamed/moved on your PC. I'd suggest reinstalling mysql(probably uninstall current copy first). If that doesn't work then, if it's possible, download a fresh copy of mySQL and reinstall. Maybe choose a different mirror to download from?
Your English is fine...and it's certainly better than my Portuguese!