...the script doesn't work.
is not very descriptive: it dies at some of your dies? what error Perl reports?
Reading your code as I understand it you tell Perl something like:
"Perl please for every file in the glob expression if it is a plain file, open it, read it and FOR EVERY occurence of a specified word copy this file to destination with File::Copy AND with the system call". you can use last after the first copy was succesfull.

More notably you are calling the system call inside single quotes ('') and not backticks (``) that you can type with ALT+96 combo.
Pay attention also to the directory separator on windows (you can safely use / instead of \ ): see Glob portabilty issues

HtH
L*