... it says vi is not internal or external command , operable program or batch file.

If 'it' (your system) says vi is not installed on the system (or not accessible from your path), you're going to have to address that issue before system will be of any use to you. (And BTW: It's  system (lower-case 's') and not 'System'; let's not stumble down that rabbit-hole!)

Update:

System(@command) == 0
or die "could not '@command':$";
[download]

Also, it should be  $? and not plain "$" at the end of the die message. See perlvar, esp. the "Error Variables" sub-section.